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1

An anechoic chamber facility for investigating aerodynamic noise  

NASA Technical Reports Server (NTRS)

The aerodynamic noise facility was designed to be used primarily for investigating the noise-generating mechanisms of high-temperature supersonic and subsonic jets. The facility consists of an anechoic chamber, an exhaust jet silencer, instrumentation equipment, and an air heater with associated fuel and cooling systems. Compressed air, when needed for jet noise studies, is provided by the wind tunnel compressor facility on a continuous basis. The chamber is 8.1 m long, 5.0 m wide, and 3.0 m high. Provisions have been made for allowing outside air to be drawn into the anechoic chamber in order to replenish the air that is entrained by the jet as it flows through the chamber. Also, openings are provided in the walls and in the ceiling for the purpose of acquiring optical measurements. Calibration of the chamber for noise reflections from the wall was accomplished in octave bands between 31.2 Hz and 32 kHz.

Massier, P. F.; Parthasarathy, S. P.

1972-01-01

2

A portable miniature anechoic chamber  

NASA Astrophysics Data System (ADS)

The portable miniature anechoic chamber (PMAC), a low-cost alternative to a full-size anechoic chamber, is presented. The PMAC is a miniature, enclosed, RF-tight microwave antenna range, which approximates the performance of an indoor range over the C through Ku (G through J)-band frequencies. The small footprint, four by six feet, allows for ease of movement by one person to a test site, indoors or outdoors. The PMAC can be used at I (intermediate)-level to support the operational readiness (OR) requirements of the U.S. Army, Navy or Air Force. In conjunction with the antenna test equipment (ATE), and under TPS control, it can be used for performance verification, fault detection and fault isolation. A typical application using the PMAC in this operating mode is described.

Lorthioir, Jack; Gavin, Paul

3

AIAA 2004-0010 Designing an Anechoic Chamber for  

E-print Network

in the chamber due to the addition of a new Make-Up Air unit. Several far field acoustic measurements. (1977)6 to study the effects of varying exit temperature and mass flow of secondary and tertiary annularAIAA 2004-0010 Designing an Anechoic Chamber for the Experimental Study of High Speed Heated Jets

Tinney, Charles E.

4

A microwave anechoic chamber for radar-cross section measurement  

Microsoft Academic Search

A microwave anechoic chamber has been developed at the Department of Electrical Engineering, University of Malaya, for monostatic and bistatic radar-cross-section measurements. The structure of the chamber is a quarter-section geodesic dome, with a 12 foot radius, and raised three feet above the floor. An antenna railing system is installed inside the chamber. The antennas can be moved along the

B. K. Chung; H. T. Chuah; J. W. Bredow

1997-01-01

5

Comparison of electromagnetic absorber used in anechoic and semi-anechoic chambers for emissions and immunity testing of digital devices  

Microsoft Academic Search

The absorber used in anechoic and semi-anechoic chambers employed for emissions and immunity testing of digital devices is examined. Using reflectivities obtained by the method of homogenization, the advantages and disadvantages of urethane pyramids, twisted-pyramids, wedges, as well as ferrite tiles, ferrite grids, and “hybrid” combinations of urethanes and ferrites, are determined. General reflectivity guidelines are also presented for comparing

Christopher L. Holloway; Ronald R. DeLyser; Robert F. German; Paul McKenna; Motohisa Kanda

1997-01-01

6

Electric field uniformity measurements for qualification of Anechoic Chamber at TBRL Chandigarh  

Microsoft Academic Search

Prior to emission and susceptibility testing, the Anechoic chamber is to be qualified and regulatory compliance tests must be performed in accordance with IEC 61000-4-3. This paper discusses about qualification of the Anechoic Chamber and describes the experimental investigations of field uniformity test conducted inside the Anechoic Chamber at TBRL, Chandigarh. A series of investigations have been carried out to

N. Sood; P. Angra; D. Kothari; O. P. Khurana

2008-01-01

7

Electronic warfare testing at the Benefield anechoic facility  

Microsoft Academic Search

This paper discusses the test capabilities of the Benefield Anechoic Facility (BAF) and its mission to support avionics and electronic warfare (EW) test and evaluation (T&E) of current and future generation manned and unmanned aerospace vehicles. Testing at the BAF can provide the dense, complex, and realistic signal environment necessary to evaluate integrated systems\\/subsystems to meet both Development Test and

Emad F. Ali; Pat Dubria; Bob Barker

1997-01-01

8

The New Anechoic Shielded Chambers Designed for Space and Commercial Applications at LIT  

NASA Technical Reports Server (NTRS)

The main objective of this paper is to present the capabilities of the new anechoic shielded rooms designed for space and commercial applications as part of the Integration and Testing Laboratory (LIT, Laboratorio de Integracao e Testes) in Brazil. A new anechoic shielded room named CBA2 has been in full operation since March 2007 and a remodeled chamber CBA1 is planned to be ready by the end of 2008, replacing an old facility which was in operation for the last 18 years. The Brazilian Space Program started with very small and simple satellites and the old CBA1 chamber was conceived in 1987 to accomplish the EMI/EMC tests not requiring significant volumes. Since the very beginning this facility was also used by the private sector for other applications mainly due to the absorption of digital electronics in all kind of products. The intense use of this facility during the last years, operating three shifts a day, caused a normal degradation and imposed several limitations. Therefore, a new totally remodeled chamber was designed considering the state of the art in terms of absorbers and associated instrumentation. On the other hand the facility CBA2 was conceived, designed and implemented to test large satellites taking into account the advance of the technology in terms of RF frequencies, power level, testing methodologies and several other factors. A very interesting and unique aspect of this project was the partnership between the private sector and governmental institution. As a result, the total investment was shared between several companies and consequently a time-sharing use of the facility as well.

da Silva, Benjamim; Galvao, M. C.; Pereira, Clovis Solano

2008-01-01

9

Fully compact anechoic chamber using the pyramidal ferrite absorber for immunity test  

Microsoft Academic Search

A new generation of electromagnetic wave absorber, which has a pyramidal shape and 10 cm in height and excellent absorbing characteristics, was developed to satisfy the required characteristics of a fully compact anechoic chamber in the wide frequency range. The material of the new absorber is composed of a ferrite powder and polypropylene. When the new absorber was cascaded on

Kazuo Shimada; Toshikatsu Hayashi; Masamitsu Tokuda

2000-01-01

10

A microwave applicator for uniform irradiation by circularly polarized waves in an anechoic chamber.  

PubMed

Microwave applicators are widely employed for materials heating in scientific research and industrial applications, such as food processing, wood drying, ceramic sintering, chemical synthesis, waste treatment, and insect control. For the majority of microwave applicators, materials are heated in the standing waves of a resonant cavity, which can be highly efficient in energy consumption, but often lacks the field uniformity and controllability required for a scientific study. Here, we report a microwave applicator for rapid heating of small samples by highly uniform irradiation. It features an anechoic chamber, a 24-GHz microwave source, and a linear-to-circular polarization converter. With a rather low energy efficiency, such an applicator functions mainly as a research tool. This paper discusses the significance of its special features and describes the structure, in situ diagnostic tools, calculated and measured field patterns, and a preliminary heating test of the overall system. PMID:25173291

Chiang, W Y; Wu, M H; Wu, K L; Lin, M H; Teng, H H; Tsai, Y F; Ko, C C; Yang, E C; Jiang, J A; Barnett, L R; Chu, K R

2014-08-01

11

A microwave applicator for uniform irradiation by circularly polarized waves in an anechoic chamber  

NASA Astrophysics Data System (ADS)

Microwave applicators are widely employed for materials heating in scientific research and industrial applications, such as food processing, wood drying, ceramic sintering, chemical synthesis, waste treatment, and insect control. For the majority of microwave applicators, materials are heated in the standing waves of a resonant cavity, which can be highly efficient in energy consumption, but often lacks the field uniformity and controllability required for a scientific study. Here, we report a microwave applicator for rapid heating of small samples by highly uniform irradiation. It features an anechoic chamber, a 24-GHz microwave source, and a linear-to-circular polarization converter. With a rather low energy efficiency, such an applicator functions mainly as a research tool. This paper discusses the significance of its special features and describes the structure, in situ diagnostic tools, calculated and measured field patterns, and a preliminary heating test of the overall system.

Chiang, W. Y.; Wu, M. H.; Wu, K. L.; Lin, M. H.; Teng, H. H.; Tsai, Y. F.; Ko, C. C.; Yang, E. C.; Jiang, J. A.; Barnett, L. R.; Chu, K. R.

2014-08-01

12

LLNL heart valve condition classification project anechoic testing results at the TRANSDEC evaluation facility  

SciTech Connect

This report first briefly outlines the procedures and support/activation fixture developed at LLNL to perform the heart valve tests in an anechoic-like tank at the US Navy Transducer Evaluation Facility (TransDec) located in San Diego, CA. Next they discuss the basic experiments performed and the corresponding experimental plan employed to gather meaningful data systematically. The signal processing required to extract the desired information is briefly developed along with some of the data. Finally, they show the results of the individual runs for each valve, point out any of the meaningful features and summaries.

Candy, J V

1999-10-31

13

X-43A Undergoing Controlled Radio Frequency Testing in the Benefield Anechoic Facility at Edwards Ai  

NASA Technical Reports Server (NTRS)

The X-43A Hypersonic Experimental (Hyper-X) Vehicle hangs suspended in the cavernous Benefield Aenechoic Facility at Edwards Air Force Base during radio frequency tests in January 2000. Hyper-X, the flight vehicle for which is designated as X-43A, is an experimental flight-research program seeking to demonstrate airframe-integrated, 'air-breathing' engine technologies that promise to increase payload capacity for future vehicles, including hypersonic aircraft (faster than Mach 5) and reusable space launchers. This multiyear program is currently underway at NASA Dryden Flight Research Center, Edwards, California. The Hyper-X schedule calls for its first flight later this year (2000). Hyper-X is a joint program, with Dryden sharing responsibility with NASA's Langley Research Center, Hampton, Virginia. Dryden's primary role is to fly three unpiloted X-43A research vehicles to validate engine technologies and hypersonic design tools as well as the hypersonic test facility at Langley. Langley manages the program and leads the technology development effort. The Hyper-X Program seeks to significantly expand the speed boundaries of air-breathing propulsion by being the first aircraft to demonstrate an airframe-integrated, scramjet-powered free flight. Scramjets (supersonic-combustion ramjets) are ramjet engines in which the airflow through the whole engine remains supersonic. Scramjet technology is challenging because only limited testing can be performed in ground facilities. Long duration, full-scale testing requires flight research. Scramjet engines are air-breathing, capturing their oxygen from the atmosphere. Current spacecraft, such as the Space Shuttle, are rocket powered, so they must carry both fuel and oxygen for propulsion. Scramjet technology-based vehicles need to carry only fuel. By eliminating the need to carry oxygen, future hypersonic vehicles will be able to carry heavier payloads. Another unique aspect of the X-43A vehicle is the airframe integration. The body of the vehicle itself forms critical elements of the engine. The forebody acts as part of the intake for airflow and the aft section serves as the nozzle. The X-43A vehicles were manufactured by Micro Craft, Inc., Tullahoma, Tennessee. Orbital Sciences Corporation, Chandler, Arizona, built the Pegasus rocket booster used to launch the X-43 vehicles. For the Dryden research flights, the Pegasus rocket booster and attached X-43 will be air launched by Dryden's B-52 'Mothership.' After release from the B-52, the booster will accelerate the X-43A vehicle to the established test conditions (Mach 7 to 10) at an altitude of approximately 100,000 feet where the X-43 will separate from the booster and fly under its own power and preprogrammed control.

2000-01-01

14

Indian LSSC (Large Space Simulation Chamber) facility  

NASA Technical Reports Server (NTRS)

The Indian Space Agency has undertaken a major project to acquire in-house capability for thermal and vacuum testing of large satellites. This Large Space Simulation Chamber (LSSC) facility will be located in Bangalore and is to be operational in 1989. The facility is capable of providing 4 meter diameter solar simulation with provision to expand to 4.5 meter diameter at a later date. With such provisions as controlled variations of shroud temperatures and availability of infrared equipment as alternative sources of thermal radiation, this facility will be amongst the finest anywhere. The major design concept and major aspects of the LSSC facility are presented here.

Brar, A. S.; Prasadarao, V. S.; Gambhir, R. D.; Chandramouli, M.

1988-01-01

15

Electromagnetic test facilities at Sandia National Laboratories  

Microsoft Academic Search

The paper describes major electromagnetic test facilities at Sandia National Laboratories; each has undergone recent upgrades. The paper discusses each facility, their uses, and upgrades pertaining to the facilities performance and diagnostic capabilities. The facilities discussed are the Sandia lightning simulator, the electromagnetic environments simulator (a large TEM cell), the mode-stirred chamber, and the anechoic chamber. Sandia's expertise in electromagnetics

Michele Caldwell; Matthew B. Higgins

2005-01-01

16

Making an anechoic choral recording  

NASA Astrophysics Data System (ADS)

The utilization of auralization as a tool for acoustic analysis continues to grow and develop. An important element for successful auralization listening experiences is the selection of anechoic source material. In researching the current library of anechoically recorded source material, it was discovered that choral material was not readily available. The Wenger Corporation, St. Olaf College, and 3M undertook a joint project to create an anechoic choral recording. The paper describes the challenges of this recording project-from the technological, logistical, and musical standpoints-and the solutions that were successfully implemented.

Freiheit, Ron; Alexander, John; Ferguson, John

2005-09-01

17

Electromagnetic Radiation (EMR) coupling to complex systems : aperture coupling into canonical cavities in reverberant and anechoic environments and model validation.  

SciTech Connect

Mode-stirred chamber and anechoic chamber measurements were made on two sets of canonical test objects (cylindrical and rectangular) with varying numbers of thin slot apertures. The shielding effectiveness was compared to determine the level of correction needed to compensate the mode-stirred data to levels commensurate with anechoic data from the same test object.

Charley, Dawna R.; Higgins, Matthew B.

2007-12-01

18

Anechoic Chamber o Echoless Room, existing equipment  

E-print Network

Simple Circuits Gyroscopes Engineering in the brain o NeuroPathways etc. Science in PopCulture o that is played without being touched Fastest way to cool a pop o Design a cool quick way to cool canned

Saskatchewan, University of

19

The Kevlar-walled anechoic wind tunnel  

NASA Astrophysics Data System (ADS)

The aerodynamic and acoustic performance of an anechoic wind tunnel test section with walls made from thin Kevlar cloth have been measured and analyzed. The Kevlar test section offers some advantages over a conventional free-jet arrangement. The cloth contains the bulk of the flow but permits the transmission of sound with little loss. The containment results in smaller far-field aerodynamic corrections meaning that larger models can be tested at higher Reynolds numbers. The containment also eliminates the need for a jet catcher and allows for a much longer test section. Model-generated noise is thus more easily separated from facility background using beamforming. Measurements and analysis of acoustic and aerodynamic corrections for a Kevlar-walled test section are presented and discussed, along with benchmark trailing edge noise measurements.

Devenport, William J.; Burdisso, Ricardo A.; Borgoltz, Aurelien; Ravetta, Patricio A.; Barone, Matthew F.; Brown, Kenneth A.; Morton, Michael A.

2013-08-01

20

An Absorbing Boundary Condition Based on Anechoic Absorber For EM Scattering Computation  

Microsoft Academic Search

A novel absorbing boundary condition (ABC), to be used with finite difference and finite element electromagnetic radiation and scattering problems is described. It is based on anechoic chamber absorber foam geometry, with specified complex permittivity and permeability. The advantage of this absorbing boundary is that it prevents reflections from much wider incident angles than currently used lattice termination conditions. Since

C. M. Rappaport; L. J. Bahrmasel

1992-01-01

21

Anechoic aquarium for ultrasonic neural telemetry.  

PubMed Central

An acoustic neural telemetry tag has been developed for recording from free-swimming aquatic animals. Microwire electrodes were implanted into the VIIIth nerve of the toadfish, Opsanus tau, and interfaced to the subdermally implanted tag. The telemetry tag frequency modulates the neural signal, converting it into a varying frequency, which is amplified and transmitted acoustically (centre frequency of 90 kHz and a 20 kHz bandwidth). This acoustic signal is detected by a receiver hydrophone, and the receiver reconstructs the full neural waveform from the acoustic signal. However, due to the multipath environment in the experimental aquarium, the acoustic signal is quickly degraded as the hydrophone is moved away from the source. In order to receive the signal independent of fish position, an anechoic aquarium was designed. Streams of microbubbles (ca. 70 microm diameter) were generated to produce a curtain of sound-absorptive material along the walls and water surface of the aquarium. Microbubble generation significantly reduced the multipath artefacts, and allowed signal discrimination independent of fish and hydrophone position. The anechoic aquarium will allow the recording of neural activity from free-swimming fishes in quasi-natural habitats, thus allowing better understanding of the neural mechanisms of behaviour. PMID:11079420

Mensinger, A F; Deffenbaugh, M

2000-01-01

22

3.0 GROWTH FACILITY SPACE REQUESTS Prospective users of the greenhouses or growth chambers are encouraged to  

E-print Network

, they will be presented to the Plant Growth Facilities Committee for arbitration. A. Fees, Rates and Other Charges Space and the Plant Growth Facilities Committee. Greenhouse and growth chamber space charges are levied based3.0 GROWTH FACILITY SPACE REQUESTS Prospective users of the greenhouses or growth chambers

Pawlowski, Wojtek

23

The crop growth research chamber: A ground-based facility for CELSS research  

NASA Technical Reports Server (NTRS)

A ground based facility for the study of plant growth and development under stringently controlled environments is being developed by the Closed Ecological Life Support System (CELSS) program at the Ames Research Center. Several Crop Growth Research Chambers (CGRC) and laboratory support equipment provide the core of this facility. The CGRC is a closed (sealed) system with a separate recirculating atmosphere and nutrient delivery systems. The atmospheric environment, hydroponic environment, systems controls, and data acquisition are discussed.

Bubenheim, David L.

1990-01-01

24

Analysis of electromagnetic pulse (EMP) measurements in the National Ignition Facility's target bay and chamber  

NASA Astrophysics Data System (ADS)

From May 2009 to the present we have recorded electromagnetic pulse (EMP) strength and spectrum (100 MHz - 5 GHz) in the target bay and chamber of the National Ignition Facility (NIF). The dependence of EMP strength and frequency spectrum on target type and laser energy is discussed. The largest EMP measured was for relatively low-energy, short-pulse (100 ps) flat targets.

Brown, C. G.; Clancy, T. J.; Eder, D. C.; Ferguson, W.; Throop, A. L.

2013-11-01

25

ATMOSPHERIC CHEMISTRY OF POTENTIAL EMISSIONS FROM FUEL CONVERSION FACILITIES. A SMOG CHAMBER STUDY  

EPA Science Inventory

The atmospheric chemistry of chemical species that may be emitted from fuel conversion facilities were studied in smog chambers. Of 17 compounds assessed for ozone-forming potential, 6 compounds were selected along with a control species, propylene, for testing in the presence of...

26

Characterization of the Reverberation Chamber at the NASA Langley Structural Acoustics Loads and Transmission (SALT) Facility  

NASA Technical Reports Server (NTRS)

In 2011 the noise generating capabilities in the reverberation chamber of the Structural Acoustic Loads and Transmission (SALT) facility at NASA Langley Research Center were enhanced with two fiberglass reinforced polyester resin exponential horns, each coupled to Wyle Acoustic Source WAS-3000 airstream modulators. This report describes the characterization of the reverberation chamber in terms of the background noise, diffusivity, sound pressure levels, the reverberation times and the related overall acoustic absorption in the empty chamber and with the acoustic horn(s) installed. The frequency range of interest includes the 80 Hz to 8000 Hz one-third octave bands. Reverberation time and sound pressure level measurements were conducted and standard deviations from the mean were computed. It was concluded that a diffuse field could be produced above the Schroeder frequency in the 400 Hz one-third octave band and higher for all applications. This frequency could be lowered by installing panel diffusers or moving vanes to improve the acoustic modal overlap in the chamber. In the 80 Hz to 400 Hz one-third octave bands a successful measurement will be dependent on the type of measurement, the test configuration, the source and microphone locations and the desired accuracy. It is recommended that qualification measurements endorsed in the International Standards be conducted for each particular application.

Grosveld, Ferdinand W.

2013-01-01

27

Ion-chamber-based loss monitor system for the Los Alamos Meson Physics Facility  

SciTech Connect

A new loss monitor system has been designed and installed at the Los Alamos Meson Physics Facility (LAMPF). The detectors are ion chambers filled with N{sub 2} gas. The electronics modules have a threshold range of 1:100, and they can resolve changes in beam loss of about 2% of the threshold settings. They can generate a trip signal in 2 {mu}s if the beam loss is large enough; if the response time of the Fast Protect System is included the beam will be shut off in about 37 {mu}s.

Plum, M.A.; Brown, D.; Browman, A.; Macek, R.J.

1995-05-01

28

Anechoic wind tunnel study of turbulence effects on wind turbine broadband noise  

NASA Technical Reports Server (NTRS)

This paper describes recent results obtained at MIT on the experimental and theoretical modelling of aerodynamic broadband noise generated by a downwind rotor horizontal axis wind turbine. The aerodynamic broadband noise generated by the wind turbine rotor is attributed to the interaction of ingested turbulence with the rotor blades. The turbulence was generated in the MIT anechoic wind tunnel facility with the aid of biplanar grids of various sizes. The spectra and the intensity of the aerodynamic broadband noise have been studied as a function of parameters which characterize the turbulence and of wind turbine performance parameters. Specifically, the longitudinal integral scale of turbulence, the size scale of turbulence, the number of turbine blades, and free stream velocity were varied. Simultaneous measurements of acoustic and turbulence signals were made. The sound pressure level was found to vary directly with the integral scale of the ingested turbulence but not with its intensity level. A theoretical model based on unsteady aerodynamics is proposed.

Loyd, B.; Harris, W. L.

1995-01-01

29

SHIELDING ANALYSIS FOR X-RAY SOURCES GENERATED IN TARGET CHAMBER OF THE NATIONAL IGNITION FACILITY  

SciTech Connect

Prompt doses from x-rays generated as result of laser beam interaction with target material are calculated at different locations inside the National Ignition Facility (NIF). The maximum dose outside a Target Chamber diagnostic port is {approx} 1 rem for a shot utilizing the 192 laser beams and 1.8 MJ of laser energy. The dose during a single bundle shot (8 laser beams) drops to {approx} 40 mrem. Doses calculated outside the Target Bay doors and inside the Switchyards (except for the 17 ft.-6 in. level) range from a fraction of mrem to about 11 mrem for 192 beams, and scales down proportionally with smaller number of beams. At the 17ft.-6 in. level, two diagnostic ports are directly facing two of the Target Bay doors and the maximum doses outside the doors are 51 and 15.5 mrem, respectively. Shielding each of the two Target Bay doors with 1/4 in. Pb reduces the dose by factor of fifty. One or two bundle shots (8 to 16 laser beams) present a small hazard to personnel in the Switchyards.

Khater, H Y; Brereton, S J; Singh, M S

2008-03-27

30

Processing of Prosthetic Heart Valve Sounds from Anechoic Tank Measurements  

SciTech Connect

People with serious cardiac problems have had their life span extended with the development of the prosthetic heart valve. However, the valves operate continuously at approximately 39 million cycles per year and are therefore subject to structural failures either by faulty design or material fatigue. The development of a non-invasive technique using an acoustic contact microphone and sophisticated signal processing techniques has been proposed and demonstrated on limited data sets. In this paper we discuss an extension of the techniques to perform the heart valve tests in an anechoic like. Here the objective is to extract a ''pure'' sound or equivalently the acoustical vibration response of the prosthetic valves in a quiet environment. The goal is to demonstrate that there clearly exist differences between values which have a specific mechanical defect known as single leg separation (SLS) and non-defective valves known as intact (INT). We discuss the signal processing and results of anechoic acoustic measurements on 50 prosthetic valves in the tank. Finally, we show the results of the individual runs for each valve, point out any of the meaningful features that could be used to distinguish the SLS from INT and summarize the experiments.

Candy, J V; Meyer, A W

2001-03-20

31

Basic features of electromagnetic pulse generated in a laser-target chamber at 3-TW laser facility PALS  

NASA Astrophysics Data System (ADS)

We describe the radiofrequency emission taking place when 300 ps laser pulses irradiate various solid targets with an intensity of 1016 W/cm2. The emission of intense electromagnetic pulses was observed outside the laser target chamber by two loop antennas up to 1 GHz. Electromagnetic pulses can be 800 MHz transients, which decay from a peak electromagnetic field of E0 ? 7 kV/m and H0 ? 15 A/m. The occurrence of these electromagnetic pulses is associated with generation of hard x-rays with photon energies extending beyond 1 MeV. This contribution reports the first observation of this effect at the PALS facility.

De Marco, M.; Pfeifer, M.; Krousky, E.; Krasa, J.; Cikhardt, J.; Klir, D.; Nassisi, V.

2014-04-01

32

Ultra-light duct for an anechoic wind tunnel  

NASA Technical Reports Server (NTRS)

A tunnel ultra-light (or TUL) is a duct composed of acoustically transparent cloth designed to transform an open-jet wind tunnel into a closed-jet wind tunnel. This concept is of interest (a priori) for anechoic wind tunnels because it improves the aerodynamic quality without hindering the measurement of sound in the far field. A full scale device designed for the 3 m diameter test section of CEPRA 19 was described. The apparatus installation did not develop any significant problems, and the mechanical support turned out to be excellent. Aerodynamic and acoustic tests are discussed. Certain imperfections in the installation as tested - instabilities above 25 m/s and acceptable cloth transmission up to 4kHz were revealed. The system as tested could eventually be used in certain applications, for example, in ground based transport. However, the concept of TUL must be developed further to arrive at a reliable mechanism for use in a large number of applications.

Lambourion, J.; Lewy, S.; Papirnyk, O.; Rahier, G.; Remandet, J.-N.

1989-01-01

33

A Concept for a Low Pressure Noble Gas Fill Intervention in the IFE Fusion Test Facility (FTF) Target Chamber  

SciTech Connect

An engineering evaluation has been initiated to investigate conceptual engineering methods for implementing a viable gas shield strategy in the Fusion Test Facility (FTF) target chamber. The employment of a low pressure noble gas in the target chamber to thermalize energetic helium ions prior to interaction with the wall could dramatically increase the useful life of the first wall in the FTF reactor1. For the purpose of providing flexibility, two target chamber configurations are addressed: a five meter radius sphere and a ten meter radius sphere. Experimental studies at Nike have indicated that a low pressure, ambient gas resident in the target chamber during laser pulsing does not appear to impair the ability of laser light from illuminating targets2. In addition, current investigations into delivering, maintaining, and processing low pressure gas appear to be viable with slight modification to current pumping and plasma exhaust processing technologies3,4. Employment of a gas fill solution for protecting the dry wall target chamber in the FTF may reduce, or possibly eliminate the need for other attenuating technologies designed for keeping He ions from implanting in first wall structures and components. The gas fill concept appears to provide an effective means of extending the life of the first wall while employing mostly commercial off the shelf (COTS) technologies. Although a gas fill configuration may provide a methodology for attenuating damage inflicted on chamber surfaces, issues associated with target injection need to be further analyzed to ensure that the gas fill concept is viable in the integrated FTF design5. In the proposed system, the ambient noble gas is heated via the energetic helium ions produced by target detonation. The gas is subsequently cooled by the chamber wall to approximately 800oC, removed from the chamber, and processed by the chamber gas processing system (CGPS). In an optimized scenario of the above stated concept, the chamber wall acts as the primary heat exchanger. During removal, gas is pumped through the laser ports by turbo molecular-drag pumps (TM-DP). For the purpose of reducing organic based lubricants and seals, a magnetically levitated TM-DP is being investigated with pump manufacturers. Currently, magnetically levitated turbo molecular pumps are commercially available. The pumps will be exposed to thermal loads and ionizing radiation (tritium, Ar-41, post detonation neutrons). Although the TM-DP's will be subjected to these various radiations, current designs for similar pumping devices have been hardened and have the ability of locating control electronics in remote radiation shielded enclosures4. The radiation hardened TM-DP's will be 5 required to operate with minimal maintenance for periods of up to 18 continuous months. As part of this initial investigation for developing a conceptual engineering strategy for a gas fill solution, commercial suppliers of low pressure gas pumping systems have been contacted and engaged in this evaluation. Current technology in the area of mechanical pumping systems indicates that the development of a robust pumping system to meet the requirements of the FTF gas fill concept is within the limits of COTS equipment3,4.

C.A. Gentile, W.R. Blanchard, T.A. Kozub, M. Aristova, C. McGahan, S. Natta, K. Pagdon, J. Zelenty

2010-01-14

34

Numerical simulation on a massively parallel computer, of printed antennas in an anechoic chamber  

NASA Astrophysics Data System (ADS)

The report presents results obtained during the past year on the Transmission Line Matrix method. It also describes a second method, the Prony-Pisarenko method, widely used to determine mathematical models from signals, and to calculate frequency spectra. Lastly, it presents details and the operation of the massively parallel Connection Machine, as well as describes the Johns matrix method.

Vasta, R.

35

Mars and Lunar Vacuum Chamber Testing Facilities and Vacuum Rated Drill Systems  

NASA Astrophysics Data System (ADS)

Martian and Lunar low pressure and vacuum conditions, respectively, greatly affect the performance of the drilling mechanics and drill hardware. For this reason, it is imperative to test planetary sampling and coring drills under these specific environments. Honeybee Robotics acquired an 11ft vacuum chamber that is currently being used to test drills to 1m depth and more. A separate cooling system is used to maintain low temperature of planetary analog formations such as ice, soil, icy-soils, and rocks. The low temperature increases the strength of these formations and in turn reduces drilling efficiency. The chamber also has a numerous feed troughs that can be used to transfer thermal data from thermocouples embedded inside the drilled sample, and the drill bits. The thermal data is useful to determine the temperature the sample reaches during the drilling process. The drill systems include rotary, rotary-percussive, and rotary-sonic. The latter two, in particular, offer superior performance in hard formations due to impacts and/or vibrations that enhance penetration rate. All the drill systems are vacuum rated and hence can be used as test platforms for vacuum testing.

Zacny, K.; Paulsen, G.; Craft, J.; Maksymuk, M.; Santoro, C.; Wilson, J.

2009-12-01

36

Development and tests of interferometry facility in 6-m diameter radiometer thermal vacuum chamber in Tsukuba Space Center  

NASA Astrophysics Data System (ADS)

We present a test of optical metrology for 800-mm spaceborne optics in the 6-m radiometer thermal vacuum chamber at JAXA's Tsukuba Space Center of JAXA. Under the framework of the JAXA's large-optics study program for astronomy and Earth observations, we developed a test bench for interferometric metrology of large optics with an auto-collimation method in the chamber. The optical system was aligned in a horizontal light-axis configuration within the facility limit to handle a 3.5-m aperture telescope like SPICA. A high-speed interferometer was contained in an aluminum and titanmade pressure vessel, which was mounted on the five-axis stage. We tested the 800-mm lightweight C/SiC optics using a 900-mm diameter flat mirror. Alignment changes in tilts of about ten arcseconds were observed as pressure went down from 1 atm to vacuum. After we re-aligned the interferometer and flat mirror, the wavefronts through the optics under vacuum were observed to increase in astigmatism aberration by 0.07?RMS at ?=633nm from under atmosphere, which might be caused by a deformation in the test optics or flat mirror.

Suganuma, Masahiro; Katayama, Haruyoshi; Naitoh, Masataka; Imai, Tadashi; Miyamoto, Masashi; Maruyama, Kenta; Kaneda, Hidehiro; Tange, Yoshio; Nakagawa, Takao

2010-07-01

37

Archiving Quality Control Tests in the PHENIX Resistive Plate Chamber Assembly Facility  

NASA Astrophysics Data System (ADS)

The PHENIX collaboration at RHIC studies polarized proton-proton collisions to better understand the spin structure of the proton. PHENIX is in the process of upgrading the muon trigger to improve our capabilities of selecting the muons from the decay of W-bosons which are produced more readily at a high transverse momentum than other muon sources. By triggering on single, high transverse momentum muons, new observations on the spin asymmetries of a proton can be obtained. The trigger upgrade will consist of four stations of Resistive Plate Chambers (RPCs), with stations on each side of the interaction region. Each RPC consists of two Bakelite gas gaps, a copper signal plane, an aluminum case, and several layers of mylar and copper. With all of these parts comes the need to archive the manufacturing and quality assurance information along with test results performed on them. This information is kept in a Postgresql Database in the RPC factory and is maintained, modified, and read out through several PHP web pages. A new output page has been produced that will make all of this information much more accessible. This poster will focus on what data is archived, how it is stored, and how it can be easily retrieved and put to use.

Andrews, Keller

2009-10-01

38

The V-3 contamination test of the chamber A facility and a subsequent cryogenic/vacuum study of the V-3 test quartz crystal microbalance  

NASA Technical Reports Server (NTRS)

The areas of orbital and ground contamination of flight experiment hardware have been well established. This report relates directly to results of vacuum chamber testing for the ground evaluation of flight experiment hardware performance. First, the data obtained during the V-3 contamination testing in the Johnson Space Center's Chamber A space simulation test facility are presented. Second, during the V-3 contamination tests, the MSFC Space Sciences Laboratory's quartz crystal microbalance exhibited two periods of anomalous readings. Therefore, a subsequent small chamber tests was conducted in a controlled cryogenic/vacuum environment. The objective was to reproduce with known parameters the anomalous behavior patterns of the V-3 test data. Analyses of the anomalous readings are made on the basis of these tests. Additionally, as a by-product of the small chamber tests, calibration curves then existing for the quartz crystal microbalance were empirically extended, and certain data-formatting aids were documented.

Moore, W. W., Jr.; Tashbar, P. W.

1973-01-01

39

Acoustic anechoic layers with singly periodic array of scatterers: Computational methods, absorption mechanisms, and optimal design  

NASA Astrophysics Data System (ADS)

The acoustic properties of anechoic layers with a singly periodic array of cylindrical scatterers are investigated. A method combined plane wave expansion and finite element analysis is extended for out-of-plane incidence. The reflection characteristics of the anechoic layers with cavities and locally resonant scatterers are discussed. The backing is a steel plate followed by an air half space. Under this approximate zero transmission backing condition, the reflection reduction is induced by the absorption enhancement. The absorption mechanism is explained by the scattering/absorption cross section of the isolated scatterer. Three types of resonant modes which can induce efficient absorption are revealed. Due to the fact that the frequencies of the resonant modes are related to the size of the scatterers, anechoic layers with scatterers of mixed size can broaden the absorption band. A genetic optimization algorithm is adopted to design the anechoic layer with scatterers of mixed size at a desired frequency band from 2 kHz to 10 kHz for normal incidence, and the influence of the incident angle is also discussed.

Yang, Hai-Bin; Li, Yue; Zhao, Hong-Gang; Wen, Ji-Hong; Wen, Xi-Sen

2014-10-01

40

Flow chamber  

DOEpatents

A flow chamber having a vacuum chamber and a specimen chamber. The specimen chamber may have an opening through which a fluid may be introduced and an opening through which the fluid may exit. The vacuum chamber may have an opening through which contents of the vacuum chamber may be evacuated. A portion of the flow chamber may be flexible, and a vacuum may be used to hold the components of the flow chamber together.

Morozov, Victor (Manassas, VA)

2011-01-18

41

Capabilities, Design, Construction and Commissioning of New Vibration, Acoustic, and Electromagnetic Capabilities Added to the World's Largest Thermal Vacuum Chamber at NASA's Space Power Facility  

NASA Technical Reports Server (NTRS)

NASA s human space exploration plans developed under the Exploration System Architecture Studies in 2005 included a Crew Exploration Vehicle launched on an Ares I launch vehicle. The mass of the Crew Exploration Vehicle and trajectory of the Ares I coupled with the need to be able to abort across a large percentage of the trajectory generated unprecedented testing requirements. A future lunar lander added to projected test requirements. In 2006, the basic test plan for Orion was developed. It included several types of environment tests typical of spacecraft development programs. These included thermal-vacuum, electromagnetic interference, mechanical vibration, and acoustic tests. Because of the size of the vehicle and unprecedented acoustics, NASA conducted an extensive assessment of options for testing, and as result, chose to augment the Space Power Facility at NASA Plum Brook Station, of the John H. Glenn Research Center to provide the needed test capabilities. The augmentation included designing and building the World s highest mass capable vibration table, the highest power large acoustic chamber, and adaptation of the existing World s largest thermal vacuum chamber as a reverberant electromagnetic interference test chamber. These augmentations were accomplished from 2007 through early 2011. Acceptance testing began in Spring 2011 and will be completed in the Fall of 2011. This paper provides an overview of the capabilities, design, construction and acceptance of this extraordinary facility.

Motil, Susan M.; Ludwiczak, Damian R.; Carek, Gerald A.; Sorge, Richard N.; Free, James M.; Cikanek, Harry A., III

2011-01-01

42

Markov-chain Monte Carlo identification of favorable design choices with application to anechoic coatings.  

PubMed

Global optimization methods can be used to numerically determine optimal design parameters for an object. However, this does not by itself give a good appreciation of other parameter choices that may be almost as good and even preferable from other points of view. In the present paper, Markov-chain Monte Carlo methods are used to go beyond the optimal solution and create an ensemble of object models in parameter space that covers a set of favorable models uniformly. In direct analogy with applications to Bayesian inversion with determination of an unknown posterior probability density, projections of the model ensemble onto parameter axes and planes are used to exhibit parameter sensitivities and dependencies. Design of anechoic rubber coatings, with cylinder cavities having axes in a lateral direction, is considered as a particular application. The anechoic effect is evaluated by the efficient layer-multiple-scattering method, which is extended to handle cylinder scatterers of noncircular cross sections and mixed types. As anticipated by computed scattering and absorption cross sections for an isolated cavity, the favorable coatings have oblate cavity cross-section shapes, which is useful to achieve good low-frequency reflection reduction with a thin coating. PMID:24907797

Ivansson, Sven M

2014-06-01

43

Performance of the high speed anechoic wind tunnel at Lyon University  

NASA Technical Reports Server (NTRS)

The characteristics of the feed duct, the wind tunnel, and the experiments run in the convergent-divergent anechoic wind tunnel at Lyon University are described. The wind tunnel was designed to eliminate noise from the entrance of air or from flow interactions with the tunnel walls so that noise caused by the flow-test structure interactions can be studied. The channel contains 1 x 1 x 0.2 m glass and metal foil baffles spaced 0.2 m apart. The flow is forced by a 350 kW fan in the primary circuit, and a 110 kW blower in the secondary circuit. The primary circuit features a factor of four throat reductions, followed by a 1.6 reduction before the test section. Upstream and downstream sensors permit monitoring of the anechoic effectiveness of the channel. Other sensors allow modeling of the flow structures in the tunnel. The tunnel was used to examine turbulent boundary layers in flows up to 140 m/sec, tubulence-excited vibrations in walls, and the effects of laminar and turbulent flows on the appearance and locations of noise sources.

Sunyach, M.; Brunel, B.; Comte-Bellot, G.

1986-01-01

44

Binaural Simulation Experiments in the NASA Langley Structural Acoustics Loads and Transmission Facility  

NASA Technical Reports Server (NTRS)

A location and positioning system was developed and implemented in the anechoic chamber of the Structural Acoustics Loads and Transmission (SALT) facility to accurately determine the coordinates of points in three-dimensional space. Transfer functions were measured between a shaker source at two different panel locations and the vibrational response distributed over the panel surface using a scanning laser vibrometer. The binaural simulation test matrix included test runs for several locations of the measuring microphones, various attitudes of the mannequin, two locations of the shaker excitation and three different shaker inputs including pulse, broadband random, and pseudo-random. Transfer functions, auto spectra, and coherence functions were acquired for the pseudo-random excitation. Time histories were acquired for the pulse and broadband random input to the shaker. The tests were repeated with a reflective surface installed. Binary data files were converted to universal format and archived on compact disk.

Grosveld, Ferdinand W.; Silcox, Richard (Technical Monitor)

2001-01-01

45

Wire chamber  

DOEpatents

A wire chamber or proportional counter device, such as Geiger-Mueller tube or drift chamber, improved with a gas mixture providing a stable drift velocity while eliminating wire aging caused by prior art gas mixtures. The new gas mixture is comprised of equal parts argon and ethane gas and having approximately 0.25% isopropyl alcohol vapor.

Atac, Muzaffer (Wheaton, IL)

1989-01-01

46

Anechoic coatings obtained from two- and three-dimensional monopole resonance diffraction gratings.  

PubMed

Underwater sound reflections can be reduced in magnitude by a rubber coating including three-dimensional (3-D) cavities forming a doubly periodic diffraction grating. A monopole resonance for sphere-like cavities enhances absorption in the surrounding rubber solid. A corresponding resonance for an infinite cylinder is studied in the present paper. Appearing at a considerably lower frequency than for a sphere with the same radius, it suggests the possibility of much thinner anechoic coatings including cylindrical cavities, with axes in a lateral direction, forming a diffraction grating with a single period. This is effectively a 2-D case, because of invariance in the axial direction. Subsequent coating design computations, using the layer-multiple-scattering method and including cavities of different sizes, show improved reflection reduction with coatings only about one third as thick. Still accounting for multiple scattering among the cavities and capturing the essential physics, the monopole approximation is applied to advance the analytic study of the reflection reduction. An energy decomposition relation is derived and used to quantify the absorption of the incident sound energy by cavities of different sizes. Coatings based on filled inclusions and other resonance effects are briefly considered. Again, the 2-D alternative with cylinders of mixed sizes gives thinner coatings. PMID:22501043

Ivansson, Sven M

2012-04-01

47

Anechoic Sphere Phantoms for Estimating 3-D Resolution of Very High Frequency Ultrasound Scanners  

PubMed Central

Two phantoms have been constructed for assessing the performance of high frequency ultrasound imagers. They also allow for periodic quality assurance tests. The phantoms contain eight blocks of tissue-mimicking material where each block contains a spatially random distribution of suitably small anechoic spheres having a small distribution of diameters. The eight mean sphere diameters are distributed from 0.10 to 1.09 mm. The two phantoms differ primarily in terms of the backscatter coefficient of the background material in which the spheres are suspended. The mean scatterer diameter for one phantom is larger than that for the other phantom resulting in a lesser increase in backscatter coefficient for the second phantom; however, the backscatter curves cross at about 35 MHz. Since spheres have no preferred orientation, all three (spatial) dimensions of resolution contribute to sphere detection on an equal basis; thus, the resolution is termed 3-D. Two high frequency scanners are compared. One employs single-element (fixed focus) transducers, and the other employs variable focus linear arrays. The nominal frequency for the single element transducers were 25 and 55 MHz and for the linear array transducers were 20, 30 and 40 MHz. The depth range for detection of spheres of each size is determined corresponding to determination of 3-D resolution as a function of depth. As expected, the single-element transducers are severely limited in useful imaging depth ranges compared with the linear arrays. Note that these phantoms could also be useful for training technicians in using higher frequency scanners. PMID:20889416

Madsen, Ernest L.; Frank, Gary R.; McCormick, Matthew M.; Deaner, Meagan E.; Stiles, Timothy A.

2013-01-01

48

The development of a wind tunnel facility for the study of V/STOL noise  

E-print Network

An open-jet wind tunnel operating within an anechoic chamber was developed for the purpose of the study of V/STOL noise mechanisms. An existing low-speed conventional hard-walled wind tunnel was modified to operate as an ...

Widnall, S. E.

1972-01-01

49

Emulating an Anechoic Environment in a Wave-Diffusive Medium through an Extended  

E-print Network

to a series of impinging wavefronts with varying features. Electromagnetic compatibility, antenna testing) or in electromagnetic compatibility (e.g., vehicles) requires complex mechanical solutions. A class of testing configur. The proposed alternative technique, named Time-Reversal Electromagnetic Chamber (TREC) is introduced

Boyer, Edmond

50

Chamber propagation  

SciTech Connect

Propagation of a heavy ion beam to the target appears possible under conditions thought to be realizable by several reactor designs. Beam quality at the lens is believed to provide adequate intensity at the target -- but the beam must pass through chamber debris and its self fields along the way. This paper reviews present consensus on propagation modes and presents recent results on the effects of photoionization of the beam ions by thermal x-rays from the heated target. Ballistic propagation through very low densities is a conservative mode. The more-speculative self-pinched mode, at 1 to 10 Torr, offers reactor advantages and is being re-examined by others. 13 refs.

Langdon, B.

1991-01-16

51

Chamber transport  

SciTech Connect

Heavy ion beam transport through the containment chamber plays a crucial role in all heavy ion fusion (HIF) scenarios. Here, several parameters are used to characterize the operating space for HIF beams; transport modes are assessed in relation to evolving target/accelerator requirements; results of recent relevant experiments and simulations of HIF transport are summarized; and relevant instabilities are reviewed. All transport options still exist, including (1) vacuum ballistic transport, (2) neutralized ballistic transport, and (3) channel-like transport. Presently, the European HIF program favors vacuum ballistic transport, while the US HIF program favors neutralized ballistic transport with channel-like transport as an alternate approach. Further transport research is needed to clearly guide selection of the most attractive, integrated HIF system.

OLSON,CRAIG L.

2000-05-17

52

Research and test facilities  

NASA Technical Reports Server (NTRS)

A description is given of each of the following Langley research and test facilities: 0.3-Meter Transonic Cryogenic Tunnel, 7-by 10-Foot High Speed Tunnel, 8-Foot Transonic Pressure Tunnel, 13-Inch Magnetic Suspension & Balance System, 14-by 22-Foot Subsonic Tunnel, 16-Foot Transonic Tunnel, 16-by 24-Inch Water Tunnel, 20-Foot Vertical Spin Tunnel, 30-by 60-Foot Wind Tunnel, Advanced Civil Transport Simulator (ACTS), Advanced Technology Research Laboratory, Aerospace Controls Research Laboratory (ACRL), Aerothermal Loads Complex, Aircraft Landing Dynamics Facility (ALDF), Avionics Integration Research Laboratory, Basic Aerodynamics Research Tunnel (BART), Compact Range Test Facility, Differential Maneuvering Simulator (DMS), Enhanced/Synthetic Vision & Spatial Displays Laboratory, Experimental Test Range (ETR) Flight Research Facility, General Aviation Simulator (GAS), High Intensity Radiated Fields Facility, Human Engineering Methods Laboratory, Hypersonic Facilities Complex, Impact Dynamics Research Facility, Jet Noise Laboratory & Anechoic Jet Facility, Light Alloy Laboratory, Low Frequency Antenna Test Facility, Low Turbulence Pressure Tunnel, Mechanics of Metals Laboratory, National Transonic Facility (NTF), NDE Research Laboratory, Polymers & Composites Laboratory, Pyrotechnic Test Facility, Quiet Flow Facility, Robotics Facilities, Scientific Visualization System, Scramjet Test Complex, Space Materials Research Laboratory, Space Simulation & Environmental Test Complex, Structural Dynamics Research Laboratory, Structural Dynamics Test Beds, Structures & Materials Research Laboratory, Supersonic Low Disturbance Pilot Tunnel, Thermal Acoustic Fatigue Apparatus (TAFA), Transonic Dynamics Tunnel (TDT), Transport Systems Research Vehicle, Unitary Plan Wind Tunnel, and the Visual Motion Simulator (VMS).

1993-01-01

53

Quality assurance procedures for environmental control and monitoring in plant growth facilities. Report of the North Central Regional 101 Committee on Growth Chamber Use  

NASA Technical Reports Server (NTRS)

This report includes procedures for ensuring the quality of the environment provided for plant growth in controlled environment facilities. Biologists and engineers may use these procedures for ensuring quality control during experiments or for ensuring quality control in the design of plant growth facilities. Environmental monitoring prior to and during experiments is included in these procedures. Specific recommendations cover control, acquisition, and calibration for sensor types for the separate parameters of radiation (light), temperature, humidity, carbon dioxide, and air movement.

Tibbitts, T. W. (Principal Investigator)

1986-01-01

54

A large hemi-anechoic enclosure for community-compatible aeroacoustic testing of aircraft propulsion systems  

NASA Astrophysics Data System (ADS)

A large hemianechoic (absorptive walls and acoustically hard floor) noise control enclosure was erected around a complex of test stands at the NASA Lewis Research Center in Cleveland, Ohio. This new state-of-the art Aeroacoustic Propulsion Laboratory (APL) provides an all-weather, semi secure test environment while limiting noise to acceptable levels in surrounding residential neighborhoods. The 39.6-m- (130-ft-) diameter geodesic dome houses the new nozzle aeroacoustic test rig (NATR), an ejector-powered Mach 0.3 free jet facility for acoustic testing of supersonic aircraft exhaust nozzles and turbomachinery. A multiaxis, force-measuring, powered lift facility (PLF) stand for testing short takeoff vertical-landing (STOVL) vehicles is also located in the dome. The design of the Aeroacoustic Propulsion Laboratory efficiently accommodates the research functions of two separate test rigs, one of which (NATR) requires a specialized environment for taking acoustic measurements. An absorptive fiberglass wedge treatment on the interior surface of the dome provides a hemianechoic environment for obtaining the accurate acoustic measurements required to meet research program goals. The APL is the first known geodesic dome structure to incorporate transmission-loss properties as well as interior absorption in a free-standing, community-compatible, hemianechoic test facility.

Cooper, Beth A.

1993-04-01

55

Characterization of the spatial resolution of different high-frequency imaging systems using a novel anechoic-sphere phantom.  

PubMed

The spatial resolution of high-frequency ultrasound (HFU, >20 MHz) imaging systems is usually determined using wires perpendicular to the beam. Recently, two tissue-mimicking phantoms (TMPs) were developed to estimate three-dimensional (3-D) resolution. Each TMP consists of nine 1-cm-wide slabs of tissue-mimicking material containing randomly distributed anechoic spheres. All anechoic spheres in one slab have the same dimensions, and their diameter is increased from 0.1 mm in the first slab to 1.09 mm in the last. The scattering background for one set of slabs was fabricated using 3.5-?m glass beads; the second set used 6.4-?m glass beads. The ability of a HFU system to detect these spheres against a speckle background provides a realistic estimation of its 3-D spatial resolution. In the present study, these TMPs were used with HFU systems using single-element transducers, linear arrays, and annular arrays. The TMPs were immersed in water and each slab was scanned using two commercial imaging systems and a custom HFU system based on a 5-element annular array. The annular array had a nominal center frequency of 40 MHz, a focal length of 12 mm, and a total aperture of 6 mm. A synthetic-focusing algorithm was used to form images with an increased depth-of-field. The penetration depth was increased by using a linear-chirp signal spanning 15 to 65 MHz over 4 ?s. Results obtained with the custom system were compared with those of the commercial systems (40-MHz probes) in terms of sphere detection, i.e., 3-D spatial resolution, and contrast-to-noise ratio (CNR). Resulting B-mode images indicated that only the linear-array transducer failed to clearly resolve the 0.2-mm spheres, which showed that the 3-D spatial resolution of the single-element and annular-array transducers was superior to that of the linear array. The single-element transducer could only detect these spheres over a narrow 1.5 mm depth-of-field, whereas the annular array was able to detect them to depths of at least 7 mm. For any size of the anechoic spheres, the annular array excited by a chirp-coded signal provided images of the highest contrast, with a maximum CNR of 1.8 at the focus, compared with 1.3 when using impulse excitation and 1.6 with the single-element transducer and linear array. This imaging configuration also provided CNRs above 1.2 over a wide depth range of 8 mm, whereas CNRs would quickly drop below 1 outside the focal zone of the other configurations. PMID:21622055

Filoux, Erwan; Mamou, Jonathan; Aristizábal, Orlando; Ketterling, Jeffrey A

2011-05-01

56

Portable Hyperbaric Chamber  

NASA Technical Reports Server (NTRS)

A portable, collapsible hyperbaric chamber was developed. A toroidal inflatable skeleton provides initial structural support for the chamber, allowing the attendant and/or patient to enter the chamber. Oval hatches mate against bulkhead rings, and the hyperbaric chamber is pressurized. The hatches seal against an o-ring, and the internal pressure of the chamber provides the required pressure against the hatch to maintain an airtight seal. In the preferred embodiment, the hyperbaric chamber has an airlock to allow the attendant to enter and exit the patient chamber during treatment. Visual communication is provided through portholes in the patient and/or airlock chamber. Life monitoring and support systems are in communication with the interior of the hyperbaric chamber and/or airlock chamber through conduits and/or sealed feed-through connectors into the hyperbaric chamber.

Schneider, William C. (Inventor); Locke, James P. (Inventor); DeLaFuente, Horacio (Inventor)

2001-01-01

57

Elongated chambers for field studies across atmospheric CO2 gradients  

Microsoft Academic Search

Summary 1. We describe a field facility that controls CO 2 along continuous gradients from superambient to subambient concentrations. The facility consists of two transparent, tunnel-shaped chambers, each 1-m wide and tall and 60-m long. Pure CO 2 is injected into one chamber during daylight to initiate a superambient CO 2 gradient (550-350 ? mol mol -1 ). Ambient air

H. B. Johnson; H. W. Polley; R. P. Whitis

2000-01-01

58

TRU waste characterization chamber gloveboxes.  

SciTech Connect

Argonne National Laboratory-West (ANL-W) is participating in the Department of Energy's (DOE) National Transuranic Waste Program in support of the Waste Isolation Pilot Plant (WIPP). The Laboratory's support currently consists of intrusive characterization of a selected population of drums containing transuranic waste. This characterization is performed in a complex of alpha containment gloveboxes termed the Waste Characterization Gloveboxes. Made up of the Waste Characterization Chamber, Sample Preparation Glovebox, and the Equipment Repair Glovebox, they were designed as a small production characterization facility for support of the Idaho National Engineering and Environmental Laboratory (INEEL). This paper presents salient features of these gloveboxes.

Duncan, D. S.

1998-07-02

59

The Cloud Chamber  

NSDL National Science Digital Library

This web "booklet" from the University of Cambridge provides a description of the experiments of physicist Charles Thomson Rees Wilson that led to the first succesful cloud chamber, a powerful tool for nuclear and elementary particle physics. The site offers interactive graphics to help show how these chambers work. Photos and excerpts from some of Wilson's first publications are also included as well.

2008-09-23

60

Static diffusion cloud chambers  

NASA Astrophysics Data System (ADS)

The chamber geometry and optical arrangement are described. The supersaturation range is given and consists of readings taken at five fixed points: 0.25%, 0.5%, 0.75%, 1.0%, and 1.25%. The detection system is described including light source, cameras, and photocell detectors. The temperature control and the calibration of the chamber are discussed.

Ayers, G.

1981-11-01

61

High resolution drift chambers  

SciTech Connect

High precision drift chambers capable of achieving less than or equal to 50 ..mu..m resolutions are discussed. In particular, we compare so called cool and hot gases, various charge collection geometries, several timing techniques and we also discuss some systematic problems. We also present what we would consider an ''ultimate'' design of the vertex chamber. 50 refs., 36 figs., 6 tabs.

Va'vra, J.

1985-07-01

62

Semiconductor drift chambers  

SciTech Connect

Semiconductor drift chambers for position and energy measurements have been invented, built and tested. A short 'Ccount is here given on the principles of the drift chamber and on the experimental results. Detailed reports have been written on the quoted bibliography and new reports will be published shortly.

Lutz, G.; Goulding, F.; Luke, P.N.; Madden, N.W.; Waltor, J.; Wylie, A.

1985-04-01

63

16. NBS TOPSIDE CONTROL ROOM, THE NBS HYPERBARIC CHAMBER IS ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

16. NBS TOPSIDE CONTROL ROOM, THE NBS HYPERBARIC CHAMBER IS VERY CLOSE TO THE WATER'S EDGE AND HERE FOR DIVER EMERGENCY SUPPORT. A MEDICAL STAFF IS LOCATED ON THE MARSHALL SPACE FLIGHT CENTER (MSFC) AND SUPPORTS THE NBS PERSONNEL WHEN HYPERBARIC CHAMBER OPERATION IS NECESSARY. - Marshall Space Flight Center, Neutral Buoyancy Simulator Facility, Rideout Road, Huntsville, Madison County, AL

64

The Mars Chamber  

NASA Video Gallery

The Mars chamber is a box about the size of a refrigerator that re-creates the temperatures, pressures, and atmosphere of the Martian surface, essentially creating a Mars environment on Earth! Scie...

65

Mercury Chamber Considerations  

E-print Network

Mercury Chamber Considerations V. Graves IDS-NF Target Studies July 2011 #12;2 Managed by UT-Battelle for the U.S. Department of Energy Mercury Chamber Considerations, July 2011 Flow Loop Review · 1 cm dia nozzle, 20 m/s jet requires 1.57 liter/sec mercury flow (94.2 liter/min, 24.9 gpm). · MERIT experiment

McDonald, Kirk

66

Antipollution combustion chamber  

SciTech Connect

The invention concerns a combustion chamber for turbojet engines. The combustion chamber is of the annular type and consists of two coaxial flame tubes opening into a common dilution and mixing zone. The inner tube is designed for low operating ratings of the engine, the outer tube for high ratings. Air is injected as far upstream as possible into the dilution zone, to enhance the homogenization of the gaseous flow issuing from the two tubes prior to their passage into the turbine and to assure the optimum radial distribution of temperatures. The combustion chamber according to the invention finds application in a particularly advantageous manner in turbojet engines used in aircraft propulsion because of the reduced emission of pollutants it affords.

Caruel, J.E.; Gastebois, P.M.

1981-01-27

67

Filament wound rocket motor chambers  

NASA Technical Reports Server (NTRS)

The design, analysis, fabrication and testing of a Kevlar-49/HBRF-55A filament wound chamber is reported. The chamber was fabricated and successfully tested to 80% of the design burst pressure. Results of the data reduction and analysis from the hydrotest indicate that the chamber design and fabrication techniques used for the chamber were adequate and the chamber should perform adequately in a static test.

1976-01-01

68

Bubble Chamber Site  

NSDL National Science Digital Library

This substantial site features a large number of photos of bubble chamber (BC) tracks, many with a discussion of the physics. There is a description of how the BC works and also useful tutorial on reading BC pictures. The high quality of the images and the explanations of the events that are shown make this site especially valuable.

2006-06-19

69

Phototherapy irradiation chamber  

Microsoft Academic Search

A phototherapy irradiation chamber having substantial uniformity of irradiance therewithin comprises an array of vertical fluorescent lamps surrounding the irradiation space. Reflectors are located within the array at the top and bottom thereof. The ends of the lamps extend beyond the reflectors. 8 claims.

1978-01-01

70

The KLOE drift chamber  

Microsoft Academic Search

The stringent requirements of the KLOE experiment on dimensions, efficiency, resolution and transparency of its drift chamber led to building a tracking device which can be considered innovative from many points of view.Details of the design and construction of this detector, together with preliminary results from the test of its full scale prototype, constructed and operated under a test beam

A. Andryakov; A. Antonelli; R. Baldini-Ferroli; G. Bencivenni; L. Bucci; A. Calcaterra; P. L Campana; S Dell'Agnello; R De Sangro; P De Simone; G. Felici; C. Forti; G. Finocchiaro; V. Kulikov; S. Moccia; A. Nedosekin; V. Patera; M. Piccolo; A. Denig; M. Imhof; W. Kluge; U Von Hagel; S. Weseler; G. Cataldi; P. Creti; V. Elia; V. Golovatyuk; E. Gorini; F. Grancagnolo; M. Panareo; M. Primavera; S. Spagnolo; C. Bacci; F. Ceradini; E De Lucia; F La Cava; C. Luisi; G. Margutti; D. Picca; L. Pontecorvo; R. Messi; L. Paoluzi; E. Pasqualucci; P. Valente

1996-01-01

71

Improved wire chamber  

DOEpatents

An improved gas mixture for use with proportional counter devices, such as Geiger-Mueller tubes and drift chambers. The improved gas mixture provides a stable drift velocity while eliminating wire aging caused by prior art gas mixtures. The new gas mixture is comprised of equal parts argon and ethane gas and having approximately 0.25% isopropyl alcohol vapor. 2 figs.

Atac, M.

1987-05-12

72

Liquid Wall Chambers  

SciTech Connect

The key feature of liquid wall chambers is the use of a renewable liquid layer to protect chamber structures from target emissions. Two primary options have been proposed and studied: wetted wall chambers and thick liquid wall (TLW) chambers. With wetted wall designs, a thin layer of liquid shields the structural first wall from short ranged target emissions (x-rays, ions and debris) but not neutrons. Various schemes have been proposed to establish and renew the liquid layer between shots including flow-guiding porous fabrics (e.g., Osiris, HIBALL), porous rigid structures (Prometheus) and thin film flows (KOYO). The thin liquid layer can be the tritium breeding material (e.g., flibe, PbLi, or Li) or another liquid metal such as Pb. TLWs use liquid jets injected by stationary or oscillating nozzles to form a neutronically thick layer (typically with an effective thickness of {approx}50 cm) of liquid between the target and first structural wall. In addition to absorbing short ranged emissions, the thick liquid layer degrades the neutron flux and energy reaching the first wall, typically by {approx}10 x x, so that steel walls can survive for the life of the plant ({approx}30-60 yrs). The thick liquid serves as the primary coolant and tritium breeding material (most recent designs use flibe, but the earliest concepts used Li). In essence, the TLW places the fusion blanket inside the first wall instead of behind the first wall.

Meier, W R

2011-02-24

73

Multi-chamber deposition system  

DOEpatents

A system for the simultaneous deposition of different coatings onto a thin web within a large volume vacuum chamber is disclosed which chamber is provided with a plurality of deposition chambers in which the different layers are deposited onto the film as its moves from a supply roll to a finished take-up roll of coated web. The deposition chambers provided within the large vacuum chamber are provided with separate seals which minimize back diffusion of any dopant gas from adjacent deposition chambers.

Jacobson, Richard L. (Roseville, MN); Jeffrey, Frank R. (Shoreview, MN); Westerberg, Roger K. (Cottage Grove, MN)

1989-10-17

74

Multi-chamber deposition system  

DOEpatents

A system for the simultaneous deposition of different coatings onto a thin web within a large volume vacuum chamber is disclosed which chamber is provided with a plurality of deposition chambers in which the different layers are deposited onto the film as its moves from a supply roll to a finished take-up roll of coated web. The deposition chambers provided within the large vacuum chamber are provided with separate seals which minimize back diffusion of any dopant gas from adjacent deposition chambers.

Jacobson, Richard L. (Roseville, MN); Jeffrey, Frank R. (Shoreview, MN); Westerberg, Roger K. (Cottage Grove, MN)

1989-06-27

75

Combustor with fuel preparation chambers  

NASA Technical Reports Server (NTRS)

An annular combustor having fuel preparation chambers mounted in the dome of the combustor. The fuel preparation chamber comprises an annular wall extending axially from an inlet to an exit that defines a mixing chamber. Mounted to the inlet are an air swirler and a fuel atomizer. The air swirler provides swirled air to the mixing chamber while the atomizer provides a fuel spray. On the downstream side of the exit, the fuel preparation chamber has an inwardly extending conical wall that compresses the swirling mixture of fuel and air exiting the mixing chamber.

Zelina, Joseph (Inventor); Myers, Geoffrey D. (Inventor); Srinivasan, Ram (Inventor); Reynolds, Robert S. (Inventor)

2001-01-01

76

Multiwire proportional chamber development  

NASA Technical Reports Server (NTRS)

The development of large area multiwire proportional chambers, to be used as high resolution spatial detectors in cosmic ray experiments is described. A readout system was developed which uses a directly coupled, lumped element delay-line whose characteristics are independent of the MWPC design. A complete analysis of the delay-line and the readout electronic system shows that a spatial resolution of about 0.1 mm can be reached with the MWPC operating in the strictly proportional region. This was confirmed by measurements with a small MWPC and Fe-55 X-rays. A simplified analysis was carried out to estimate the theoretical limit of spatial resolution due to delta-rays, spread of the discharge along the anode wire, and inclined trajectories. To calculate the gas gain of MWPC's of different geometrical configurations a method was developed which is based on the knowledge of the first Townsend coefficient of the chamber gas.

Doolittle, R. F.; Pollvogt, U.; Eskovitz, A. J.

1973-01-01

77

Using the Nova target chamber for high-yield targets  

SciTech Connect

The existing 2.2-m-radius Nova aluminum target chamber, coated and lined with boron-seeded carbon shields, is proposed for use with 1000-MJ-yield targets in the next laser facility. The laser beam and diagnostic holes in the target chamber are left open and the desired 10/sup -2/ Torr vacuum is maintained both inside and outside the target chamber; a larger target chamber room is the vacuum barrier to the atmosphere. The hole area available is three times that necessary to maintain a maximum fluence below 12 J/cm/sup 2/ on optics placed at a radius of 10 m. Maximum stress in the target chamber wall is 73 MPa, which complies with the intent of the ASME Pressure Vessel Code. However, shock waves passing through the inner carbon shield could cause it to comminute. We propose tests and analyses to ensure that the inner carbon shield survives the environment. 13 refs.

Pitts, J.H.

1987-09-28

78

Wire chambers revisited.  

PubMed

Detectors used for radioisotope imaging have, historically, been based on scintillating crystal/photomultiplier combinations in various forms. From the rectilinear scanner through to modern gamma cameras and positron cameras, the basic technology has remained much the same. Efforts to overcome the limitations of this form of technology have foundered on the inability to reproduce the required sensitivity, spatial resolution and sensitive area at acceptable cost. Multiwire proportional chambers (MWPCs) have long been used as position-sensitive charged particle detectors in nuclear and high-energy physics. MWPCs are large-area gas-filled ionisation chambers in which large arrays of fine wires are used to measure the position of ionisation produced in the gas by the passage of charged particles. The important properties of MWPCs are high-spatial-resolution, large-area, high-count-rate performance at low cost. For research applications, detectors several metres square have been built and small-area detectors have a charged particle resolution of 0.4 mm at a count rate of several million per second. Modification is required to MWPCs for nuclear medicine imaging. As gamma rays or X-rays cannot be detected directly, they must be converted into photo- or Compton scatter electrons. Photon-electron conversion requires the use of high atomic number materials in the body of the chamber. Pressurised xenon is the most useful form of "gas only" photon-electron convertor and has been used successfully in a gamma camera for the detection of gamma rays at energies below 100 keV. This camera has been developed specifically for high-count-rate first-pass cardiac imaging. This high-pressure xenon gas MWPC is the key to a highly competitive system which can outperform scintillator-based systems. The count rate performance is close to a million counts per second and the intrinsic spatial resolution is better than the best scintillator-based camera. The MWPC camera produces quantitative ejection fraction information of the highest quality. The detection of higher energy gamma rays has proved more problematical, needing a solid photon-electron convertor to be incorporated into the chamber. Several groups have been working on this problem with modest success so far. The only clinical detectors have been developed for positron emission tomography, where thin lead or lead-glass can provide an acceptable convertor for 511 keV photons. Two MWPC positron cameras have been evaluated clinically and one is now in routine use in clinical oncology. The problems of detection efficiency have not been solved by these detectors although reliability and large-area PET imaging have been proven.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:8491229

Ott, R J

1993-04-01

79

Ionization chamber dosimeter  

DOEpatents

A method for fabricating an ion chamber dosimeter collecting array of the type utilizing plural discrete elements formed on a uniform collecting surface which includes forming a thin insulating layer over an aperture in a frame having surfaces, forming a predetermined pattern of through holes in the layer, plating both surfaces of the layer and simultaneously tilting and rotating the frame for uniform plate-through of the holes between surfaces. Aligned masking and patterned etching of the surfaces provides interconnects between the through holes and copper leads provided to external circuitry.

Renner, Tim R. (Berkeley, CA); Nyman, Mark A. (Berkeley, CA); Stradtner, Ronald (Kensington, CA)

1991-01-01

80

Iran Chamber Society  

NSDL National Science Digital Library

In 2001, the Iran Chamber Society was created in order to provide a non-partisan, non-commercial, comprehensive source of information on Iran. The website's "About Us" section states that their aim is to "create a global awareness about Iranian society and eradicate the misunderstandings and misconceptions about Iranian society, and to play an educational role as well." Visitors will find the website divided up into "Art and Culture", "History", "Society" and "Iran's Guide". The "Exhibitions and Conferences" link on the right side of the homepage leads visitors to a number of exhibitions, including the fascinating "Artistic Murals of Tehran's Metro Stations", which offers a dozen pictures of the beautifully handcrafted murals made of pottery, metal, cement and other materials. The "History" section offers pictures and documents, including some disturbing graphic photos from the Iran-Iraq War in 1980-1988 that appear at the end of the Historic Periods and Events section.

81

The Juelich large Aerosol Chamber  

Microsoft Academic Search

The large Aerosol Chamber is designed for the investigation of nighttime atmospheric chemistry. The Aerosol Chamber is a dark chamber and is operated at ambient temperature and pressure conditions. It is constructed as a double wall system: a fully welded aluminum box (7m x 7m x 5.3m) and an equally sized fully heat sealed Teflon bag hanging from the ceiling.

Th. Mentel; A. Wahner; M. Folkers

2003-01-01

82

HATCH CONNECTING TEMPERED AIR CHAMBER AND HOT AIR CHAMBER OF ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

HATCH CONNECTING TEMPERED AIR CHAMBER AND HOT AIR CHAMBER OF PLENUM WITH ATTACHED DRAFT REGULATOR. - Hot Springs National Park, Bathhouse Row, Superior Bathhouse: Mechanical & Piping Systems, State Highway 7, 1 mile north of U.S. Highway 70, Hot Springs, Garland County, AR

83

Preparation, verification, and operational control of a large space-environment-simulation chamber for contamination sensitive tests  

NASA Technical Reports Server (NTRS)

A 2-year program to prepare chamber A at the NASA Manned Spacecraft Center for Apollo telescope mount thermal-vacuum tests is discussed. This program covers modification to existing chamber systems, the development of facility and chamber operating procedures, the selection of chamber cleaning and control methods, and the development and evaluation of diagnostic instrumentation. Extensive efforts to ensure a minimum contamination environment for the Apollo telescope mount test series are illustrated. Recent thermal-vacuum tests of this chamber at progressive stages of cleanliness have demonstrated the success achieved in reducing the particulate and molecular contamination levels of the basic chamber interior.

Visentine, J. T.; Ogden, J. W.; Ritter, M. L.; Smith, C. F.

1972-01-01

84

13. VIEW OF VACUUM CHAMBER AND WELDING EQUIPMENT IN MODULE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

13. VIEW OF VACUUM CHAMBER AND WELDING EQUIPMENT IN MODULE E. PARTS WERE WELDED UNDER A VACUUM TO PREVENT CORROSION. (11/6/73) - Rocky Flats Plant, Plutonium Manufacturing Facility, North-central section of Plant, just south of Building 776/777, Golden, Jefferson County, CO

85

OUTDOOR SMOG CHAMBER EXPERIMENTS TO TEST PHOTOCHEMICAL MODELS: PHASE 2  

EPA Science Inventory

The smog chamber facility of the University of North Carolina was used to provide experimental data for developing and testing kinetic mechanisms of photochemical smog formation. In this study, 128 pairs of experiments were performed using NOx and various hydrocarbons and hydroca...

86

Validation of a Three-Dimensional Transmission Line Matrix (TLM) Model Implementation of a Mode-Stirred Reverberation Chamber  

Microsoft Academic Search

Reverberation chambers are attractive electromagnetic compatibility test facilities, both economically and technically. Careful design and analysis of these facilities are important, if the results obtained are to be treated with a high level of confidence. Numerical modeling is an important part of the process of reverberation chamber design and analysis. Hence, it is important that the modeling techniques to be

Alyse Coates; Hugh G. Sasse; Dawn E. Coleby; Alistair P. Duffy; Antonio Orlandi

2007-01-01

87

Proton beam monitor chamber calibration  

NASA Astrophysics Data System (ADS)

The first goal of this paper is to clarify the reference conditions for the reference dosimetry of clinical proton beams. A clear distinction is made between proton beam delivery systems which should be calibrated with a spread-out Bragg peak field and those that should be calibrated with a (pseudo-)monoenergetic proton beam. For the latter, this paper also compares two independent dosimetry techniques to calibrate the beam monitor chambers: absolute dosimetry (of the number of protons exiting the nozzle) with a Faraday cup and reference dosimetry (i.e. determination of the absorbed dose to water under IAEA TRS-398 reference conditions) with an ionization chamber. To compare the two techniques, Monte Carlo simulations were performed to convert dose-to-water to proton fluence. A good agreement was found between the Faraday cup technique and the reference dosimetry with a plane-parallel ionization chamber. The differences—of the order of 3%—were found to be within the uncertainty of the comparison. For cylindrical ionization chambers, however, the agreement was only possible when positioning the effective point of measurement of the chamber at the reference measurement depth—i.e. not complying with IAEA TRS-398 recommendations. In conclusion, for cylindrical ionization chambers, IAEA TRS-398 reference conditions for monoenergetic proton beams led to a systematic error in the determination of the absorbed dose to water, especially relevant for low-energy proton beams. To overcome this problem, the effective point of measurement of cylindrical ionization chambers should be taken into account when positioning the reference point of the chamber. Within the current IAEA TRS-398 recommendations, it seems advisable to use plane-parallel ionization chambers—rather than cylindrical chambers—for the reference dosimetry of pseudo-monoenergetic proton beams.

Gomà, C.; Lorentini, S.; Meer, D.; Safai, S.

2014-09-01

88

OUTDOOR CHAMBER STUDY TO TEST MULTI-DAY EFFECTS. VOLUME 3. DOCUMENTATION FOR COMPUTER-READABLE ENVIRONMENTAL CHAMBER DATA  

EPA Science Inventory

The smog chamber facilities of the University of California, Riverside were used to collect experimental data to assess the effects of multi-day irradiations on photochemical oxidant formation. This volume includes documentation on the computer-readable magnetic tape that contain...

89

National Ignition Facility system design requirements conventional facilities SDR001  

SciTech Connect

This System Design Requirements (SDR) document specifies the functions to be performed and the minimum design requirements for the National Ignition Facility (NIF) site infrastructure and conventional facilities. These consist of the physical site and buildings necessary to house the laser, target chamber, target preparation areas, optics support and ancillary functions.

Hands, J.

1996-04-09

90

X-ray diagnostics for laser plasma interaction in the target chamber of the LIL  

Microsoft Academic Search

The main features of x ray diagnostics for laser plasma interaction in the target chamber of the LIL will be presented. The LIL facility(Ligne dIntégration Laser) is located at CEA CESTA near Bordeaux in France. First laser shots at 3 w were beginning 2003. The x ray diagnostics are now being installed on the target chamber. They include: an x

Charles Reverdin; B. Angelier; J. L. Bourgade; J. Y. Boutin; M. Briat; G. Charles; A. Estadieu; D. Gontier; J. P. Le Breton; G. Lidove; B. Marchet; R. Marmoret; P. Millier; C. Remond; R. Rosch; G. Soullie; P. Stemmler; P. Troussel; B. Villette; R. Wrobel

2003-01-01

91

A large high vacuum, high pumping speed space simulation chamber for electric propulsion  

NASA Technical Reports Server (NTRS)

Testing high power electric propulsion devices poses unique requirements on space simulation facilities. Very high pumping speeds are required to maintain high vacuum levels while handling large volumes of exhaust products. These pumping speeds are significantly higher than those available in most existing vacuum facilities. There is also a requirement for relatively large vacuum chamber dimensions to minimize facility wall/thruster plume interactions and to accommodate far field plume diagnostic measurements. A 4.57 m (15 ft) diameter by 19.2 m (63 ft) long vacuum chamber at NASA Lewis Research Center is described. The chamber utilizes oil diffusion pumps in combination with cryopanels to achieve high vacuum pumping speeds at high vacuum levels. The facility is computer controlled for all phases of operation from start-up, through testing, to shutdown. The computer control system increases the utilization of the facility and reduces the manpower requirements needed for facility operations.

Grisnik, Stanley P.; Parkes, James E.

1994-01-01

92

Cyclically controlled welding purge chamber  

NASA Technical Reports Server (NTRS)

An arrangement for butt-welding cylindrical sections of large, thin-wall tanks includes a rotatable mandrel with side-by-side sets of radial position adjusters. Each set of adjusters bears on one of the tank sections adjacent the seam, to prevent the sections from sagging out-of-round. The mandrel rotates relative to the welder, so that a continuous seam is formed. A purge chamber is fixed in position behind the seam at the weld head, and is flushed with inert gas. The purge chamber includes a two-sided structure which is contiguous with the cylindrical sections and a circumferential vane to form an open-ended tube-like structure, through which the radial position adjusters pass as the mandrel and cylindrical workpiece sections rotate. The tube-like structure is formed into a chamber by a plurality of movable gates which are controlled to maintain a seal while allowing adjusters to progress through the purge chamber.

Gallagher, Robert L. (Inventor)

1996-01-01

93

Light diffusing fiber optic chamber  

DOEpatents

A light diffusion system for transmitting light to a target area. The light is transmitted in a direction from a proximal end to a distal end by an optical fiber. A diffusing chamber is operatively connected to the optical fiber for transmitting the light from the proximal end to the distal end and transmitting said light to said target area. A plug is operatively connected to the diffusing chamber for increasing the light that is transmitted to the target area.

Maitland, Duncan J. (Lafayette, CA)

2002-01-01

94

Interim Total Containment Test Fire Facility, Pantex Plant, Amarillo, Texas  

Microsoft Academic Search

This report documents the results of a test program conducted within a confinement chamber called the Interim Total Containment Test Fire Facility. The objective was to determine the effectiveness of the chamber to contain the blast loads and hazardous fragments generated by the largest high explosive (HE) charge expected to be fired within the chamber. 11 references, 7 figures, 5

A. G. Papp; J. L. Nunley; G. T. West

1984-01-01

95

40 CFR 160.45 - Test system supply facilities.  

Code of Federal Regulations, 2010 CFR

... (b) When appropriate, plant supply facilities shall be...maintaining algae and aquatic plants. (2) Facilities for plant growth, including, but not limited...greenhouses, growth chambers, light banks, and fields....

2010-07-01

96

40 CFR 160.45 - Test system supply facilities.  

Code of Federal Regulations, 2011 CFR

... (b) When appropriate, plant supply facilities shall be...maintaining algae and aquatic plants. (2) Facilities for plant growth, including, but not limited...greenhouses, growth chambers, light banks, and fields....

2011-07-01

97

40 CFR 792.45 - Test system supply facilities.  

Code of Federal Regulations, 2011 CFR

...b) When appropriate, plant supply facilities shall...maintaining algae and aquatic plants. (2) Facilities...in the protocol, for plant growth, including but not limited...greenhouses, growth chambers, light banks, and...

2011-07-01

98

40 CFR 792.45 - Test system supply facilities.  

Code of Federal Regulations, 2010 CFR

...b) When appropriate, plant supply facilities shall...maintaining algae and aquatic plants. (2) Facilities...in the protocol, for plant growth, including but not limited...greenhouses, growth chambers, light banks, and...

2010-07-01

99

40 CFR 792.45 - Test system supply facilities.  

Code of Federal Regulations, 2012 CFR

...b) When appropriate, plant supply facilities shall...maintaining algae and aquatic plants. (2) Facilities...in the protocol, for plant growth, including but not limited...greenhouses, growth chambers, light banks, and...

2012-07-01

100

40 CFR 160.45 - Test system supply facilities.  

Code of Federal Regulations, 2012 CFR

... (b) When appropriate, plant supply facilities shall be...maintaining algae and aquatic plants. (2) Facilities for plant growth, including, but not limited...greenhouses, growth chambers, light banks, and fields....

2012-07-01

101

Spectra, composition, and interactions of nuclei with magnet interaction chambers  

NASA Technical Reports Server (NTRS)

Emulsion chambers will be flown in the Astromag Facility to measure the cosmic ray composition and spectra to 10 exp 15 eV total energy and to definitively study the characteristics of nucleus-nucleus interactions above 10 exp 12 eV/n. Two configurations of emulsion chambers will be flown in the SCIN/MAGIC experiment. One chamber has an emulsion target and a calorimeter similar to those recently flown on balloons for composition and spectra measurements. The other has an identical calorimeter and a low-density target section optimized for performing rigidity measurements on charged particles produced in interactions. The transverse momenta of charged and neutral mesons, direct hadronic pairs from resonance decays and interference effects, and possible charge clustering in high-density states of matter will be studied.

Parneil, T. A.; Derrickson, J. H.; Fountain, W. F.; Roberts, F. E.; Tabuki, T.; Watts, J. W.; Burnett, T. H.; Cherry, M. C.; Dake, S.; Fuki, M.

1990-01-01

102

Emulsion Chamber Technology Experiment (ECT)  

NASA Technical Reports Server (NTRS)

The experimental objective of Emulsion Chamber Technology (ECT) was to develop space-borne emulsion chamber technology so that cosmic rays and nuclear interactions may subsequently be studied at extremely high energies with long exposures in space. A small emulsion chamber was built and flown on flight STS-62 of the Columbia in March 1994. Analysis of the several hundred layers of radiation-sensitive material has shown excellent post-flight condition and suitability for cosmic ray physics analysis at much longer exposures. Temperature control of the stack was 20 +/-1 C throughout the active control period and no significant deviations of temperature or pressure in the chamber were observed over the entire mission operations period. The unfortunate flight attitude of the orbiter (almost 90% Earth viewing) prevented any significant number of heavy particles (Z greater than or equal to 10) reaching the stack and the inverted flow of shower particles in the calorimeter has not allowed evaluation of absolute primary cosmic ray-detection efficiency nor of the practical time limits of useful exposure of these calorimeters in space to the level of detail originally planned. Nevertheless, analysis of the observed backgrounds and quality of the processed photographic and plastic materials after the flight show that productive exposures of emulsion chambers are feasible in low orbit for periods of up to one year or longer. The engineering approaches taken in the ECT program were proven effective and no major environmental obstacles to prolonged flight are evident.

Gregory, John C.; Takahashi, Yoshiyuki

1996-01-01

103

RADIATION ENVIRONMENT OF GROWTH CHAMBERS  

EPA Science Inventory

Radiation measurements with different types of meters in several controlled environment facilities have been compiled to demonstrate the problems associated with insuring uniform radiation levels in separate facilities. Data are provided for a quantum meter, three photometers, a ...

104

Mercury Chamber NF-IDS Meeting  

E-print Network

Beam Pipe and Nozzle · Small angles in nozzle beam pipe cause some mechanical issues · SC coil design Mercury Chamber Basics · Chamber serves as both jet and beam dumps ­ Chamber must encompass the nozzle tip · Penetrations (ports) into chamber ­ Nozzle ­ Hg drains (overflow and maintenance) ­ Vents (in and out) ­ Beam

McDonald, Kirk

105

Iridium-Coated Rhenium Combustion Chamber  

NASA Technical Reports Server (NTRS)

Iridium-coated rhenium combustion chamber withstands operating temperatures up to 2,200 degrees C. Chamber designed to replace older silicide-coated combustion chamber in small rocket engine. Modified versions of newer chamber could be designed for use on Earth in gas turbines, ramjets, and scramjets.

Schneider, Steven J.; Tuffias, Robert H.; Rosenberg, Sanders D.

1994-01-01

106

Major parameters affecting temperature inside inhalation chambers  

Microsoft Academic Search

These studies showed that stainless steel chamber walls were very effective at removing heat from an (380 l) inhalation chamber. Cooling the incoming air was not as effective in cooling the stainless steel chamber, because most of the heat transfer from the animals in the chamber was by thermal radiation and the cooled intake air was rapidly heated through the

D. M. Bernstein; R. T. Drew

1978-01-01

107

Feedwater preheater with two steam chambers  

Microsoft Academic Search

A description is given of a feedwater preheater, installable horizontally within a turbine exhaust steam housing, for heating feedwater by means of condensing bleeder steam from the turbine. The preheater includes inlet and outlet chambers for the feedwater both located at one side of the preheater, an outer steam chamber adjacent the inlet and outlet chambers, an inner steam chamber

H. Tratz; F. Kelp; E. Netsch

1977-01-01

108

Cone crusher chamber optimization using multiple constraints  

Microsoft Academic Search

The chamber geometry is one of the key factors that influences the performance of a cone crusher. The design of the chamber geometry should take product quality and crushing efficiency into account. In this paper the kinematics of rock material in a crushing chamber, as interparticle breakage occurs, has been analyzed and the chamber division is achieved. Based on the

Dong Gang; Huang Dongming; Fan Xiumin

2009-01-01

109

Hydrostatic Hyperbaric Chamber Ventilation System  

NASA Technical Reports Server (NTRS)

The hydrostatic hyperbaric chamber (HHC) represents the merger of several technologies in development for NASA aerospace applications, harnessed to directly benefit global health. NASA has significant experience developing composite hyperbaric chambers for a variety of applications, including the treatment of medical conditions. NASA also has researched the application of water-filled vessels to increase tolerance of acceleration forces. The combination of these two applications has resulted in the hydrostatic chamber, which has been conceived as a safe, affordable means of making hyperbaric oxygen therapy available in the developing world for the treatment of a variety of medical conditions. Specifically, hyperbaric oxygen therapy is highly-desired as a possibly curative treatment for Buruli Ulcer, an infectious condition that afflicts children in sub-Saharan Africa. Hyperbaric oxygen therapy is simply too expensive and too dangerous to implement in the developing world using standard equipment. The hydrostatic hyperbaric chamber technology changes the paradigm. The HHC differs from standard hyperbaric chambers in that the majority of its volume is filled with water which is pressurized by oxygen being supplied in the portion of the chamber containing the patient s head. This greatly reduces the amount of oxygen required to sustain a hyperbaric atmosphere, thereby making the system more safe and economical to operate. An effort was taken to develop an HHC system to apply HBOT to children that is simple and robust enough to support transport, assembly, maintenance and operation in developing countries. This paper details the concept for an HHC ventilation and pressurization system that will provide controlled pressurization of the system, and provide adequate washout of carbon dioxide while the subject is enclosed in the confined space during the administration of the medical treatment. The concept took into consideration operational complexity, safety to the patient and operating personnel, and physiological considerations. The simple schematic, comprised of easily acquired commercial hardware, supports sustainability.

Sargusingh, Miriam M.

2011-01-01

110

Manipulator For A Vacuum Chamber  

NASA Technical Reports Server (NTRS)

Rotary seal provides for external actuators. Positioner in vacuum employs four actuators; up/down, horizontal rotary, horizontal, and vertical rotary. External up/down and azimuthal actuators drives shaft entering vacuum chamber through sliding and rotating seal. Placement of actuator motors outside vacuum chamber reduces heat-removal load on system. Atop 2.5-cm-diameter shaft is stage supporting masses as great as 15 kg. Small motors on stage provide horizontal translation and rotation in vertical plane. Manipulator developed for calibrating plasma detectors by subjecting them to particle beams in vacuum. Standard, commercially available parts used.

Hunsaker, F.; Ogilvie, K.

1988-01-01

111

CHAMBERS FERRY ROADLESS AREA, TEXAS.  

USGS Publications Warehouse

A geologic and geochemical investigation of the Chambers Ferry Roadless Area, Texas was conducted. The area has probable mineral-resource potential for oil and gas and for lignite. No metallic or additional energy resources were identified in the investigation. Detailed analyses of well logs from the vicinity of the Chambers Ferry Roadless Area, in conjunction with seismic data, are necessary to determine if the subsurface stratigraphy and structure are favorable for the accumulation of oil and gas. A shallow drilling program involving coring on a close-space grid is necessary for determination of the rank and continuity of seams of lignitic sediments in the area.

Houser, B.B.; Ryan, George S.

1984-01-01

112

Simulation of Layered Magma Chambers.  

ERIC Educational Resources Information Center

The principles of magma addition and liquid layering in magma chambers can be demonstrated by dissolving colored crystals. The concepts of density stratification and apparent lack of mixing of miscible liquids is convincingly illustrated with hydrous solutions at room temperature. The behavior of interstitial liquids in "cumulus" piles can be…

Cawthorn, Richard Grant

1991-01-01

113

Chamber Music for Every Instrumentalist.  

ERIC Educational Resources Information Center

Discusses why students who play musical instruments should participate in a chamber music ensemble. Provides rationale for using small ensembles in the high school band curriculum. Focuses on the topic of scheduling, illustrating how to insert small ensembles into the lesson schedule, and how to set up a new schedule. (CMK)

Latten, James E.

2001-01-01

114

A pedagogical Multiwire Proportional Chamber  

NASA Astrophysics Data System (ADS)

The purpose of this laboratory session is to provide the basic ingredients for understanding the construction and operation of Multiwire Proportional Chambers (MWPC). During this session the students constructed and tested a simple position sensitive MWPC. Only measurements requiring rather simple hardware (amplifiers, digital oscilloscope) were made and some of them are presented.

Alfaro, R.

2006-09-01

115

A pedagogical Multiwire Proportional Chamber  

SciTech Connect

The purpose of this laboratory session is to provide the basic ingredients for understanding the construction and operation of Multiwire Proportional Chambers (MWPC). During this session the students constructed and tested a simple position sensitive MWPC. Only measurements requiring rather simple hardware (amplifiers, digital oscilloscope) were made and some of them are presented.

Alfaro, R. [Instituto de Fisica, UNAM, A.P.20-364, 01000, Mexico D.F. (Mexico)

2006-09-25

116

The TESLA Time Projection Chamber  

E-print Network

A large Time Projection Chamber is proposed as part of the tracking system for a detector at the TESLA electron positron linear collider. Different ongoing R&D studies are reviewed, stressing progress made on a new type readout technique based on Micro-Pattern Gas Detectors.

Nabil Ghodbane

2002-12-12

117

Thermal System Upgrade of the Space Environment Simulation Test Chamber  

NASA Technical Reports Server (NTRS)

The paper deals with the refurbishing and upgrade of the thermal system for the existing thermal vacuum test facility, the Space Environment Simulator, at NASA's Goddard Space Flight Center. The chamber is the largest such facility at the center. This upgrade is the third phase of the long range upgrade of the chamber that has been underway for last few years. The first phase dealt with its vacuum system, the second phase involved the GHe subsystem. The paper describes the considerations of design philosophy options for the thermal system; approaches taken and methodology applied, in the evaluation of the remaining "life" in the chamber shrouds and related equipment by conducting special tests and studies; feasibility and extent of automation, using computer interfaces and Programmable Logic Controllers in the control system and finally, matching the old components to the new ones into an integrated, highly reliable and cost effective thermal system for the facility. This is a multi-year project just started and the paper deals mainly with the plans and approaches to implement the project successfully within schedule and costs.

Desai, Ashok B.

1997-01-01

118

Hydrostatic Hyperbaric Chamber Ventilation System  

NASA Technical Reports Server (NTRS)

The hydrostatic hyperbaric chamber (HHC) represents the merger of several technologies in development for NASA aerospace applications, harnessed to directly benefit global health. NASA has significant experience developing composite hyperbaric chambers for a variety of applications. NASA also has researched the application of water-filled vessels to increase tolerance of acceleration forces. The combination of these two applications has resulted in the hydrostatic chamber, which has been conceived as a safe, affordable means of making hyperbaric oxygen therapy (HBOT) available in the developing world for the treatment of a variety of medical conditions. Specifically, HBOT is highly-desired as a possibly curative treatment for Buruli Ulcer, an infectious condition that afflicts children in sub-Saharan Africa. HBOT is simply too expensive and too dangerous to implement in the developing world using standard equipment. The HHC technology changes the paradigm. The HHC differs from standard hyperbaric chambers in that the majority of its volume is filled with water which is pressurized by oxygen being supplied in the portion of the chamber containing the patient s head. This greatly reduces the amount of oxygen required to sustain a hyperbaric atmosphere, thereby making the system more safe and economical to operate. An effort was taken to develop an HHC system to apply HBOT to children that is simple and robust enough to support transport, assembly, maintenance and operation in developing countries. This paper details the concept for an HHC ventilation and pressurization system to provide controlled pressurization and adequate washout of carbon dioxide while the subject is enclosed in the confined space during the administration of the medical treatment. The concept took into consideration operational complexity, safety to the patient and operating personnel, and physiological considerations. The simple schematic, comprised of easily acquired commercial hardware, supports sustainability.

Sarguisingh, Miriam J.

2012-01-01

119

Electromagnetic propulsion test facility  

NASA Technical Reports Server (NTRS)

A test facility for the exploration of electromagnetic propulsion concept is described. The facility is designed to accommodate electromagnetic rail accelerators of various lengths (1 to 10 meters) and to provide accelerating energies of up to 240 kiloJoules. This accelerating energy is supplied as a current pulse of hundreds of kiloAmps lasting as long as 1 millisecond. The design, installation, and operating characteristics of the pulsed energy system are discussed. The test chamber and its operation at pressures down to 1300 Pascals (10 mm of mercury) are described. Some aspects of safety (interlocking, personnel protection, and operating procedures) are included.

Gooder, S. T.

1984-01-01

120

Ames Hybrid Combustion Facility  

NASA Technical Reports Server (NTRS)

The report summarizes the design, fabrication, safety features, environmental impact, and operation of the Ames Hybrid-Fuel Combustion Facility (HCF). The facility is used in conducting research into the scalability and combustion processes of advanced paraffin-based hybrid fuels for the purpose of assessing their applicability to practical rocket systems. The facility was designed to deliver gaseous oxygen at rates between 0.5 and 16.0 kg/sec to a combustion chamber operating at pressures ranging from 300 to 900. The required run times were of the order of 10 to 20 sec. The facility proved to be robust and reliable and has been used to generate a database of regression-rate measurements of paraffin at oxygen mass flux levels comparable to those of moderate-sized hybrid rocket motors.

Zilliac, Greg; Karabeyoglu, Mustafa A.; Cantwell, Brian; Hunt, Rusty; DeZilwa, Shane; Shoffstall, Mike; Soderman, Paul T.; Bencze, Daniel P. (Technical Monitor)

2003-01-01

121

Measurement of ionization chamber absorbed dose k{sub Q} factors in megavoltage photon beams  

SciTech Connect

Purpose: Absorbed dose beam quality conversion factors (k{sub Q} factors) were obtained for 27 different types of ionization chamber. The aim was to obtain objective evidence on the performance of a wide range of chambers currently available, and potentially used for reference dosimetry, and to investigate the accuracy of the k{sub Q} calculation algorithm used in the TG-51 protocol. Methods: Measurements were made using the {sup 60}Co irradiator and Elekta Precise linac facilities at the National Research Council of Canada. The objective was to characterize the chambers over the range of energies applicable to TG-51 and determine whether each chamber met the requirements of a reference-class instrument. Chamber settling, leakage current, ion recombination and polarity, and waterproofing sleeve effects were investigated, and absorbed dose calibration coefficients were obtained for {sup 60}Co and 6, 10, and 25 MV photon beams. Only thimble-type chambers were considered in this investigation and were classified into three groups: (i) Reference chambers (''standard''0.6 cm{sup 3} Farmer-type chambers and their derivatives traditionally used for beam output calibration); (ii) scanning chambers (typically 0.1 cm{sup 3} volume chambers used for beam commissioning with 3-D scanning phantoms); and (iii) microchambers (very small volume ion chambers ({<=}0.01 cm{sup 3}) used for small field dosimetry). Results: As might be expected, 0.6 cm{sup 3} thimble chambers showed the most predictable performance and experimental k{sub Q} factors were obtained with a relative uncertainty of 0.1%. The performance of scanning and microchambers was somewhat variable. Some chambers showed very good behavior but others showed anomalous polarity and recombination corrections that are not fully explained at present. For the well-behaved chambers, agreement between measured and calculated k{sub Q} factors was within 0.4%; for some chambers, differences of more than 1% were seen that may be related to the recombination/polarity results. Use of such chambers could result in significant errors in the determination of reference dose in the clinic. Conclusions: Based on the experimental evidence obtained here, specification for a reference-class ionization chamber could be developed that would minimize the error in using a dosimetry protocol with calculated beam quality conversion factors. The experimental k{sub Q} data obtained here for a wide range of thimble chambers can be used when choosing suitable detectors for reference dosimetry and are intended to be used in the upcoming update/addendum to the AAPM TG-51 dosimetry protocol.

McEwen, Malcolm R. [Institute for National Measurement Standards, National Research Council of Canada, Ottawa, Ontario K1A 0R6 (Canada)

2010-05-15

122

Space Chambers for Crop Treatment  

NASA Technical Reports Server (NTRS)

Vacuum chambers, operated by McDonnell Douglas Corporation to test spacecraft, can also be used to dry water-soaked records. The drying temperature is low enough to allow paper to dry without curling or charging. Agricultural crops may also be dried using a spinoff system called MIVAC, which has proven effective in drying rice, wheat, soybeans, corn, etc. The system is energy efficient and can incorporate a sanitation process for destroying insects without contamination.

1985-01-01

123

Ion chamber gamma burst detector  

Microsoft Academic Search

The sensitivity of burst detection is examined with respect to the space distribution of gamma-ray bursts and to early X-ray bursts from Type I supernovae. An ion-chamber burst detector for the 2-10 keV energy range is proposed in the form of a system of three mutually orthogonal gas-filled Mylar space balloons. The proposed balloon detector has an area of 100

S. A. Colgate

1982-01-01

124

Contamination Control Assessment of the World's Largest Space Environment Simulation Chamber  

NASA Technical Reports Server (NTRS)

The Space Power Facility s thermal vacuum test chamber is the largest chamber in the world capable of providing an environment for space simulation. To improve performance and meet stringent requirements of a wide customer base, significant modifications were made to the vacuum chamber. These include major changes to the vacuum system and numerous enhancements to the chamber s unique polar crane, with a goal of providing high cleanliness levels. The significance of these changes and modifications are discussed in this paper. In addition, the composition and arrangement of the pumping system and its impact on molecular back-streaming are discussed in detail. Molecular contamination measurements obtained with a TQCM and witness wafers during two recent integrated system tests of the chamber are presented and discussed. Finally, a concluding remarks section is presented.

Snyder, Aaron; Henry, Michael W.; Grisnik, Stanley P.; Sinclair, Stephen M.

2012-01-01

125

Delay-line readout drift chambers  

NASA Astrophysics Data System (ADS)

Delay-line readout multiwire gas proportional chambers have been constructed that use drift time information to interpolate between anode wires. Position resolutions over the entire active area of the chamber of 150 ?m fwhm are routinely obtained for instantaneous event rates of up to 1 MHz. Chambers with active areas of up to 30 cm by 90 cm have been built.

Atencio, L. G.; Amann, J. F.; Boudrie, R. L.; Morris, C. L.

126

Making a Fish Tank Cloud Chamber  

ERIC Educational Resources Information Center

The cloud chambers described here are large, made from readily available parts, simple to set up and always work. With no source in the chamber, background radiation can be observed. A large chamber means that a long rod containing a weakly radioactive material can be introduced, increasing the chance of seeing decays. Details of equipment and…

Green, Frances

2012-01-01

127

Recent Advances in Chamber Science and Technology  

E-print Network

Recent Advances in Chamber Science and Technology Mohamed Abdou April 8, 2002ISFNT-6 San Diego, USA #12;Recent Advances in Chamber Science & Technology OutlineOutline · Highlights of Major World - Experiments - Analysis & Design #12;Highlights of Major World Programs on Chamber (Blanket) Technology

Abdou, Mohamed

128

Vacuum chamber for an undulator straight section  

SciTech Connect

A prototype aluminum extruded vacuum chamber for an undulator straight section of the Advanced Photon Source is described. The 52.-m long vacuum system is designed so that the undulator gap variation does not interfere with it. The chamber is gripped in a stiff close toleranced mounting structure to insure dimensional tolerance of the chamber height.

Kim, S.; Wehrle, R.; Genens, L.

1987-01-01

129

Wire chamber degradation at the Argonne ZGS  

SciTech Connect

Experience with multiwire proportional chambers at high rates at the Argonne Zero Gradient Synchrotron is described. A buildup of silicon on the sense wires was observed where the beam passed through the chamber. Analysis of the chamber gas indicated that the density of silicon was probably less than 10 ppM.

Haberichter, W.; Spinka, H.

1986-01-01

130

A Sensitive Cloud Chamber without Radioactive Sources  

ERIC Educational Resources Information Center

We present a sensitive diffusion cloud chamber which does not require any radioactive sources. A major difference from commonly used chambers is the use of a heat sink as its bottom plate. The result of a performance test of the chamber is given. (Contains 8 figures.)

Zeze, Syoji; Itoh, Akio; Oyama, Ayu; Takahashi, Haruka

2012-01-01

131

EPA GAS PHASE CHEMISTRY CHAMBER STUDIES  

EPA Science Inventory

Gas-phase smog chamber experiments are being performed at EPA in order to evaluate a number of current chemical mechanisms for inclusion in EPA regulatory and research models. The smog chambers are 9000 L in volume and constructed of 2-mil teflon film. One of the chambers is co...

132

Design and testing of a model CELSS chamber robot  

NASA Technical Reports Server (NTRS)

A robot system for use in an enclosed environment was designed and tested. The conceptual design will be used to assist in research performed by the Controlled Ecological Life Support System (CELSS) project. Design specifications include maximum load capacity, operation at specified environmental conditions, low maintenance, and safety. The robot system must not be hazardous to the sealed environment, and be capable of stowing and deploying within a minimum area of the CELSS chamber facility. This design consists of a telescoping robot arm that slides vertically on a shaft positioned in the center of the CELSS chamber. The telescoping robot arm consists of a series of links which can be fully extended to a length equal to the radius of the working envelope of the CELSS chamber. The vertical motion of the robot arm is achieved through the use of a combination ball screw/ball spline actuator system. The robot arm rotates cylindrically about the vertical axis through use of a turntable bearing attached to a central mounting structure fitted to the actuator shaft. The shaft is installed in an overhead rail system allowing the entire structure to be stowed and deployed within the CELSS chamber. The overhead rail system is located above the chamber's upper lamps and extends to the center of the CELSS chamber. The mounting interface of the actuator shaft and rail system allows the entire actuator shaft to be detached and removed from the CELSS chamber. When the actuator shaft is deployed, it is held fixed at the bottom of the chamber by placing a square knob on the bottom of the shaft into a recessed square fitting in the bottom of the chamber floor. A support boot ensures the rigidity of the shaft. Three student teams combined into one group designed a model of the CELSS chamber robot that they could build. They investigated materials, availability, and strength in their design. After the model arm and stand were built, the class performed pre-tests on the entire system. A stability pre-test was used to determine whether the model robot arm would tip over on the stand when it was fully extended. Results showed the stand tipped when 50 Newtons were applied horizontally to the top of the vertical shaft while the arm was fully extended. This proved that it was stable. Another pre-test was the actuator slip test used to determine if there is an adequate coefficient of friction between the actuator drive wheels and drive cable to enable the actuator to fully extend and retract the arm. This pre-test revealed that the coefficient of friction was not large enough to prevent slippage. Sandpaper was glued to the drive wheel and this eliminated the slippage problem. The class preformed a fit test in the CELSS chamber to ensure that the completed robot arm is capable of reaching the entire working envelope. The robot was centered in the chamber and the arm was fully extended to the sides of the chamber. The arm was also able to retract to clear the drain pipes separating the upper and lower plant trays.

Davis, Mark; Dezego, Shawn; Jones, Kinzy; Kewley, Christopher; Langlais, Mike; Mccarthy, John; Penny, Damon; Bonner, Tom; Funderburke, C. Ashley; Hailey, Ruth

1994-01-01

133

Experimental biomass burning emission assessment by combustion chamber  

NASA Astrophysics Data System (ADS)

Biomass burning is a significant source of several atmospheric gases and particles and it represents an important ecological factor in the Mediterranean ecosystem. In this work we describe the performances of a recently developed combustion chamber to show the potential of this facility in estimating the emission from wildland fire showing a case study with leaves, small branches and litter of two representative species of Mediterranean vegetation, Quercus pubescens and Pinus halepensis. The combustion chamber is equipped with a thermocouple, a high resolution balance, an epiradiometer, two different sampling lines to collect organic volatile compounds (VOCs) and particles, a sampling line connected to a Proton Transfer Reaction Mass-Spectrometer (PTR-MS) and a portable analyzer to measure CO and CO2 emission. VOCs emission were both analyzed with GC-MS and monitored on-line with PTR-MS. The preliminary qualitative analysis of emission showed that CO and CO2 are the main gaseous species emitted during the smoldering and flaming phase, respectively. Many aromatics VOCs as benzene and toluene, and many oxygenated VOC as acetaldehyde and methanol were also released. This combustion chamber represents an important tool to determine the emission factor of each plant species within an ecosystem, but also the contribution to the emissions of the different plant tissues and the kinetics of different compound emissions during the various combustion phases. Another important feature of the chamber is the monitoring of the carbon balance during the biomass combustion.

Lusini, Ilaria; Pallozzi, Emanuele; Corona, Piermaria; Ciccioli, Paolo; Calfapietra, Carlo

2014-05-01

134

Fastrac Rocket Engine Combustion Chamber Acoustic Cavities  

NASA Technical Reports Server (NTRS)

A three dimensional modal analysis was performed using finite fluid elements. The analysis shows four distinct modes of the Fastrac chamber plus cavities near the frequency of the chamber first tangential mode. The mode shapes illustrate the complexity of fluid oscillations in a three dimensional chamber and acoustic cavity. In addition, a first tangential forcing function was applied to the chamber with three different acoustic cavity fluid temperatures. It was observed that the acoustic cavity fluid temperature has a significant effect on the response of the chamber to first tangential mode oscillations.

Christensen, Eric; Nesman, Tom

1998-01-01

135

THE CIRCUMFUSION SYSTEM FOR MULTIPURPOSE CULTURE CHAMBERS  

PubMed Central

A self-contained mechanical system for circulating nutrient fluid through 12 tissue culture chambers is described in detail. This system utilizes nonperforated cellophane membranes in the chambers which separate the circulating nutrient from the tissue culture environments. The nutrient, therefore, is dialyzed through the cellophane of each chamber; some cell products are retained in the microenvironment between the closely apposed cellophane and cover slip, whereas the other cell products move from chamber to chamber in the circulating nutrient. The resultant environmental conditions directed by the circumfusion systems are highly favorable for maintaining the differentiation of chick embryo tissues over protracted periods; a number of micrographs are shown. PMID:10976203

Rose, George G.

1967-01-01

136

Portable Ethylene Oxide Sterilization Chamber  

PubMed Central

A portable ethylene oxide sterilization chamber was designed, constructed, and tested for use in the sterilization of embolectomy catheters. The unit can accommodate catheters up to 40 inches (101.6 cm) in length and can be operated for less than 4 cents per cycle. A constant concentration of 500 mg of ethylene oxide per liter of space and holding periods of 4 and 6 hr at 43 and 22 C, respectively, were adequate when tested with B. subtilis spores. The estimated cost of construction was $165.00. If temperature control is unnecessary, the cost is approximately $80.00. Images PMID:4977644

Songer, J. R.; Mathis, R. G.

1969-01-01

137

Chamber propagation physics for heavy ion fusion  

SciTech Connect

Chamber transport is an important area of study for heavy ion fusion. Final focus and chamber-transport are high leverage areas providing opportunities to significantly decrease the cost of electricity from a heavy ion fusion power plant. Chamber transport in two basic regimes is under consideration. In the low chamber density regime ({approx_lt}0.003 torr), ballistic or nearly-ballistic transport is used. Partial beam neutralization has been studied to offset the effects of beam stripping. In the high chamber density regime ({approx_gt}.1 torr), two transport modes (pinched transport and channel transport) are under investigation. Both involve focusing the beam outside the chamber then transporting it at small radius ({approx} 2 mm). Both high chamber density modes relax the constraints on the beam quality needed from the accelerator which will reduce the driver cost and the cost of electricity.

Callahan, D.A.

1995-09-01

138

Outdoor chamber study to test multi-day effects. Volume 2. Environmental chamber data tabulations. Final report, August 1982-August 1984  

SciTech Connect

The smog chamber facilities of the University of California, Riverside were used to collect experimental data to assess the effects of multi-day irradiations on photochemical oxidant formation. This volume contains the printouts of all the data that were collected in the study. These data are suitable for use in developing and testing kinetic mechanisms of photochemical smog formation.

Carter, W.P.L.; Dodd, M.C.; Long, W.D.; Atkinson, R.

1984-12-01

139

Gas-Grain Simulation Facility (GGSF)  

NASA Technical Reports Server (NTRS)

The goal of the Gas-Grain Simulation Facility project is to provide a microgravity laboratory to facilitate research relevant to exobiology (the study of the origin and evolution of life in the universe). Such a facility will also be useful in other areas of study important to NASA including planetary science, biology, atmospheric science, astrophysics, chemistry, and physics. To achieve this goal, the project will develop and support the GGSF, a modular facility-class payload planned for inclusion on Space Station Freedom. The GGSF will consist of the following: an experiment chamber(s) supported by subsystems that provide chamber environment regulation and monitoring capabilities; sample generation, injection, positioning, and retrieval capabilities; and computer control, data acquisition, and housekeeping capabilities. The facility will also provide analytical tools such as light-scattering measurement systems, aerosol size-spectrum measurement devices, and optical imaging systems.

Greenwald, Ken

1992-01-01

140

Status of the construction of the Gluex Forward Drift Chambers  

NASA Astrophysics Data System (ADS)

Currently under construction at the Thomas Jefferson National Accelerator Facility in Newport News, Virginia, the full GlueX detector is designed to study gluonic degrees of freedom through the production of ``hybrid'' mesons with exotic quantum numbers. To accomplish this task the detector requires high acceptance and reasonably good resolution for both charged and neutral particles. The core of the detector is housed within the bore of a 2.0 Tesla solenoidal magnet. Charged particles emanating from the target for angles greater than about 20 degrees with respect to the beam line will be tracked with a straw-tube detector (the Central Drift Chamber). Forward-going charged particles will be detected using the Forward Drift Chambers (FDC). I will describe the design and construction of the FDC and present preliminary resolution measurements.

Taylor, Simon

2013-04-01

141

Canister Decontamination Chamber No. 1 operability test results  

SciTech Connect

The DWPF Canister Decontamination Chamber No. 1 (CDC) was installed at the TNX facility in October, 1986 for operability testing. Operability testing was required because this equipment is unique and is a critical part of the defense waste process. The test was successful in demonstrating the canister decontamination operation. Testing verified proper nozzle locations, frit suspension, level probe and CCTV operations. The following recommendations are based on data obtained from frit blasting 24 canisters: reduce the recirculation pump speed, to allow proper level probes operation; add an extension to the chamber rinse nozzle which allows removal of frit from the top of the upper guide rinse nozzle; increase visibility through the CCTV camera; make the CMM grapple jaw pins more compatible with the MSM; and improve canister guide capability to aid in canister loading. CDC Operability Testing was completed October, 1987. 6 refs., 11 figs., 2 tabs.

Magoulas, V.E.

1987-10-30

142

MPD thrust chamber flow dynamics  

NASA Astrophysics Data System (ADS)

Flow within the thrust chamber of a Magnetoplasmadynamic (MPD) arcjet is examined experimentally and modeled with a 2-D magnetohydrodynamic code. Two quasi-steady MPD thrusters are considered under the same input conditions of current (21 kA) and total mass flow rate (0.006 kg/s, argon + 1.5 percent hydrogen). The arcjets have the same basic design, consisting of a central cathode, 3.8 cm diameter and 5 cm long, separated from a coaxial anode of equal length by a uniform gap of 2.3 cm. Two different mass injection arrangements are used (100 percent at mid-radius, and 50 percent at the cathode base, with the remainder at mid-radius). A new spectroscopic analysis procedure is developed that allows distributions of radial speed, heavy particle temperature and turbulent speed to be extracted from chordal measurements of light emission by the two species in the plasma flow. Good qualitative (and reasonable quantitative) agreement exists with distributions calculated by the MHD code, indicating that flow within the thrust chamber expands from an electromagnetically pumped plasma base (vs a pumped jet off the cathode tip). The significant variation of internal flow dynamics with mass injector arrangement implies the need for extensive experimentally validated code modeling in order to evaluate the potential performance of MPD thrusters.

1990-08-01

143

Space simulation facilities providing a stable thermal vacuum facility  

NASA Technical Reports Server (NTRS)

CBI has recently constructed the Intermediate Thermal Vacuum Facility. Built as a corporate facility, the installation will first be used on the Boost Surveillance and Tracking System (BSTS) program. It will also be used to develop and test other sensor systems. The horizontal chamber has a horseshoe shaped cross section and is supported on pneumatic isolators for vibration isolation. The chamber structure was designed to meet stability and stiffness requirements. The design process included measurement of the ambient ground vibrations, analysis of various foundation test article support configurations, design and analysis of the chamber shell and modal testing of the chamber shell. A detailed 3-D finite element analysis was made in the design stage to predict the lowest three natural frequencies and mode shapes and to identify local vibrating components. The design process is described and the results are compared of the finite element analysis to the results of the field modal testing and analysis for the 3 lowest natural frequencies and mode shapes. Concepts are also presented for stiffening large steel structures along with methods to improve test article stability in large space simulation facilities.

Tellalian, Martin L.

1990-01-01

144

7 CFR 353.9 - Standards for accreditation of non-government facilities to perform laboratory seed health...  

Code of Federal Regulations, 2010 CFR

...facility's physical plant (e.g., laboratory...of greenhouses or growth chambers where plants are grown for seed...scales, pH meters, distilled and sterile water, gas burners, an...require a greenhouse, growth chamber, or an...

2010-01-01

145

7 CFR 353.9 - Standards for accreditation of non-government facilities to perform laboratory seed health...  

Code of Federal Regulations, 2011 CFR

...facility's physical plant (e.g., laboratory...of greenhouses or growth chambers where plants are grown for seed...scales, pH meters, distilled and sterile water, gas burners, an...require a greenhouse, growth chamber, or an...

2011-01-01

146

Tubular copper thrust chamber design study  

NASA Technical Reports Server (NTRS)

The use of copper tubular thrust chambers is particularly important in high performance expander cycle space engines. Tubular chambers have more surface area than flat wall chambers, and this extra surface area provides enhanced heat transfer for additional energy to power the cycle. This paper was divided into two sections: (1) a thermal analysis and sensitivity study; and (2) a preliminary design of a selected thrust chamber configuration. The thermal analysis consisted of a statistical optimization to determine the optimum tube geometry, tube booking, thrust chamber geometry, and cooling routing to achieve the maximum upper limit chamber pressure for a 25,000 pound thrust engine. The preliminary design effort produced a layout drawing of a tubular thrust chamber that is three inches shorter than the Advanced Expander Test Bed (AETB) milled channel chamber but is predicted to provide a five percent increase in heat transfer. Testing this chamber in the AETB would confirm the inherent advantages of tubular chamber construction and heat transfer.

Masters, A. I.; Galler, D. E.

1992-01-01

147

Acoustic facilities for human factors research at NASA Langley Research Center: Description and operational capabilities  

NASA Technical Reports Server (NTRS)

A number of facilities were developed which provide a unique test capability for psychoacoustics and related human factors research. The design philosophy, physical layouts, dimensions, construction features, operating capabilities, and example applications for these facilities are described. In the exterior effects room, human subjects are exposed to the types of noises that are experienced outdoors, and in the interior effects room, subjects are exposed to the types of noises and noise-induced vibrations that are experience indoors. Subjects are also exposed to noises in an echo-free environment in the anechoic listening room. An aircraft noise synthesis system, which simulates aircraft flyover noise at an observer position on the ground, is used in conjunction with these three rooms. The passenger ride quality apparatus, a device for studying passenger response to noise and vibration in aircraft, or in other vehicles, is described.

Hubbard, H. H.; Powell, C. A.

1981-01-01

148

Ion chamber gamma burst detector  

NASA Astrophysics Data System (ADS)

The sensitivity of burst detection is examined with respect to the space distribution of gamma-ray bursts and to early X-ray bursts from Type I supernovae. An ion-chamber burst detector for the 2-10 keV energy range is proposed in the form of a system of three mutually orthogonal gas-filled Mylar space balloons. The proposed balloon detector has an area of 100 sq m, a sensitivity of 2 x 10 to the -10th erg/sq cm, a directionality of 0.0001 sr, and a Mylar thickness of 3 mg/sq cm. It is shown that the detector can extend the gamma-burst log N - log S curve down to a presumed temporal-confusion limit and can detect expected prompt Type I supernovae in galaxies at 100 Mpc at a rate of at least one per day.

Colgate, S. A.

149

Development of micro pixel chamber  

NASA Astrophysics Data System (ADS)

The novel gaseous detector "Micro Pixel Chamber (?-PIC)" has been developed for X-ray, gamma-ray and charged particle imaging. The ?-PIC is made based on a double-sided printing circuit board, by which a large size detector could be produced easily. The operation tests were performed successfully using a 3 cm×3 cm ? -PIC with a 0.4 mm pitch. The gas gain and stability were measured in these tests. There is neither gain reduction nor discharge between anode and cathode at a gain of 10 3 for 5 days continuous operation. Also, no gain decrease was observed up to 10 7 cps(counts per second)/mm 2 intense X-ray irradiation.

Ochi, Atsuhiko; Nagayoshi, Tsutomu; Koishi, Satoshi; Tanimori, Toru; Nagae, Tomofumi; Nakamura, Mirei

2002-02-01

150

Ion chamber gamma burst detector  

SciTech Connect

A gamma ray burst detector of x-ray photons 2 to 10 keV is designed to maximize area, 100 m/sup 2/, and sensitivity, 10/sup -10/ ergs cm/sup -2/ s/sup 1/2/ modest directionality, 2 x 10/sup -4/ sr, and minimize thickness, 3 mg cm/sup -2/, as a plastic space balloon ion chamber. If the log N - log S curve for gamma bursts extends as the -3/2 power, the sensitivity is limited by gamma-burst peak overlap in time so that the question of the size spectrum and isotropy is maximally tested. Supernova type I prompt x-ray bursts of congruent to 3-ms duration should be detected at a rate of several per day from supernova at a distance greater than 100 Mpc.

Colgate, S.A.

1981-08-25

151

Neutron-chamber detectors and applications  

SciTech Connect

Detector applications in Nuclear Safeguards and Waste Management have included measuring neutrons from fission and (alpha,n) reactions with well-moderated neutron proportional counters, often embedded in a slab of polyethylene. Other less-moderated geometries are useful for detecting both bare and moderated fission-source neutrons with good efficiency. The neutron chamber is an undermoderated detector design comprising a large, hollow, polyethylene-walled chamber containing one or more proportional counters. Neutron-chamber detectors are relatively inexpensive; can have large apertures, usually through a thin chamber wall; and offer very good detection efficiency per dollar. Neutron-chamber detectors have also been used for monitoring vehicles and for assaying large crates of transuranic waste. Our Monte Carlo calculations for a new application (monitoring low-density waste for concealed plutonium) illustrate the advantages of the hollow-chamber design for detecting moderated fission sources. 9 refs., 6 figs., 2 tabs.

Fehlau, P.E.; Atwater, H.F.; Coop, K.L.

1990-01-01

152

Fluidized wall for protecting fusion chamber walls  

DOEpatents

Apparatus for protecting the inner wall of a fusion chamber from microexplosion debris, x-rays, neutrons, etc. produced by deuterium-tritium (DT) targets imploded within the fusion chamber. The apparatus utilizes a fluidized wall similar to a waterfall comprising liquid lithium or solid pellets of lithium-ceramic, the waterfall forming a blanket to prevent damage of the structural materials of the chamber.

Maniscalco, James A. (Danville, CA); Meier, Wayne R. (Livermore, CA)

1982-01-01

153

New drift chamber for the KEDR detector  

NASA Astrophysics Data System (ADS)

For further implementation of physical research program at the KEDR detector and for accompanying equipment upgrade the new drift chamber is currently being developed. This main tracking and momentum-measuring system represents gas multilayer wire chamber operating in proportional mode. Design features and modifications versus existing chamber are described. Using prototype the spatial resolution in various gas mixtures is being studied. Preliminary results of spatial resolution measurements are presented.

Basok, I. Yu; Blinov, V. E.; Bykov, A. V.; Kharlamova, T. A.; Prisekin, V. G.; Rodyakin, V. A.; Savinov, G. A.; Shamov, A. G.; Todyshev, K. Yu

2014-10-01

154

The Mark II Vertex Drift Chamber  

SciTech Connect

We have completed constructing and begun operating the Mark II Drift Chamber Vertex Detector. The chamber, based on a modified jet cell design, achieves 30 {mu}m spatial resolution and <1000 {mu}m track-pair resolution in pressurized CO{sub 2} gas mixtures. Special emphasis has been placed on controlling systematic errors including the use of novel construction techniques which permit accurate wire placement. Chamber performance has been studied with cosmic ray tracks collected with the chamber located both inside and outside the Mark II. Results on spatial resolution, average pulse shape, and some properties of CO{sub 2} mixtures are presented. 10 refs., 12 figs., 1 tab.

Alexander, J.P.; Baggs, R.; Fujino, D.; Hayes, K.; Hoard, C.; Hower, N.; Hutchinson, D.; Jaros, J.A.; Koetke, D.; Kowalski, L.A.

1989-03-01

155

Thrust chamber thermal barrier coating techniques  

NASA Technical Reports Server (NTRS)

Methods for applying thermal barrier coatings to the hot-gas side wall of rocket thrust chambers in order to significantly reduce the heat transfer in high heat flux regions has been the focus of technology efforts for many years. A successful technique developed by NASA-Lewis that starts with the coating on a mandrel and then builds the thrust chamber around it by electroforming appropriate materials is described. This results in a smooth coating with exceptional adherence, as was demonstrated in hot fire rig tests. The low cycle fatigue life of chambers with coatings applied in this manner was increased dramatically compared to uncoated chambers.

Quentmeyer, Richard J.

1989-01-01

156

Thrust chamber thermal barrier coating techniques  

NASA Technical Reports Server (NTRS)

Methods for applying thermal barrier coatings to the hot-gas side wall of rocket thrust chambers in order to significantly reduce the heat transfer in high heat flux regions was the focus of technology efforts for many years. This paper describes a successful technique developed by the Lewis Research Center that starts with the coating of a mandrel and then builds the thrust chamber around it by electroforming appropriate materials. This results in a smooth coating with exceptional adherence, demonstrated in hot fire rig tests. The low cycle fatigue life of chambers with coatings applied in this manner was increased dramatically compared to uncoated chambers.

Quentmeyer, Richard J.

1988-01-01

157

Radiological analysis of the National Ignition Facility  

Microsoft Academic Search

The National Ignition Facility (NIF) will be capable of providing a laser output pulse at 0.35 μm wavelength with an energy of 1.8 MJ and a power of 500 TW. The NIF will house a multi-beamline, Nd-doped-glass laser capable of delivering such pulses into a target chamber. In the target chamber, a positioner will center a target containing fusion fuel

1993-01-01

158

The Space Power Facility  

NASA Technical Reports Server (NTRS)

When it was constructed, the Space Power Facility (SPF) was the world's largest vacuum chamber. It stands more than 122 feet high, 100 feet in diameter and provides a vacuum environment for the study of space propulsion. Originally commissioned for nuclear-electric propulsion studies, the SPF has been recommissioned for current and future use in the ongoing research and development of space propulsion systems. The SPF is located at Plum Brook Station, part of the John H. Glenn Research Center at Lewis Field, Cleveland, Ohio.

1999-01-01

159

Optical testing cryogenic thermal vacuum facility  

NASA Technical Reports Server (NTRS)

The construction of a turnkey cryogenic vacuum test facility was recently completed. The facility will be used to measure and record the surface profile of large diameter and 540 kg optics under simulated space conditions. The vacuum test chamber is a vertical stainless steel cylinder with a 3.5 diameter and a 7 m tangent length. The chamber was designed to maximize optical testing quality by minimizing the vibrations between the laser interferometer and the test specimen. This was accomplished by designing the chamber for a high natural frequency and vibration isolating the chamber. An optical test specimen is mounted on a movable presentation stage. During thermal vacuum testing, the specimen may be positioned to + or - 0.00025 cm accuracy with a fine adjustment mechanism. The chamber is evacuated by a close coupled Roots-type blower and rotary vane pump package and two cryopumps. The chamber is equipped with an optically dense gaseous nitrogen cooled thermal shroud. The thermal shroud is used to cool or warm the optical test specimen at a controlled rate. A control system is provided to automatically evacuate the chamber and cooldown the test specimen to the selected control temperature.

Dohogne, Patrick W.; Carpenter, Warren A.

1990-01-01

160

LAYOUT AND SIZING OF ESF ALCOVES AND REFUGE CHAMBERS  

SciTech Connect

The purpose of this analysis is to establish size requirements and approximate locations of Exploratory Studies Facility (ESF) test and operations alcoves, including refuge chambers during construction of the Topopah Spring (TS) loop. Preliminary conceptual layouts for non-deferred test alcoves will be developed to examine construction feasibility based on current test plans and available equipment. The final location and configuration layout for alcoves will be developed when in-situ rock conditions can be visually determined. This will be after the TBM has excavated beyond the alcove location and the rock has been exposed. The analysis will examine the need for construction of walkways and electrical alcoves in the ramps and main drift. Niches that may be required to accommodate conveyor booster drives and alignments are not included in this analysis. The analysis will develop design criteria for refuge chambers to meet MSHA requirements and will examine the strategic location of refuge chambers based on their potential use in various ESF fire scenarios. This document supersedes DI:BABE00000-01717-0200-00003 Rev 01, ''TS North Ramp Alcove and Stubout Location Analysis'' in its entirety (Reference 5-6).

John Beesley and Romeo S. Jurani

1995-08-25

161

study on trace contaminants control assembly for sealed environment chamber  

NASA Astrophysics Data System (ADS)

The biological and Physicochemical P C life support technologies are all important parts to establish a human Closed Ecological Life Support System CELSS for long-duration mission The latter has the advantages of lower power consumption lower mass and higher efficiency therefore researchers often incorporate the use of biological systems with P C life support technologies to continuously recycle air water and part of the solid waste stream generated such as the Russian BLSS and the NASA-sponsored Lunar-Mars Life Support Test Project LMLSTP In short these tests were very successful in integrating biological and P C life support technologies for long-duration life support Therefore we should use a combination of integrated biological with P C life support technologies in a human CELSS Human construction materials plants animals and soils release much trace toxic gases in a CELSS and they will inhibit plant growth and badly affect human health when their concentrations rise over their threshold levels The effect of biological trace contaminant control technologies is slower especially for a human sealed chamber because human produce much more methane and other contaminants A regenerative Trace Contaminant Control Subsystem TCCS with P C technology is a more important part in this case to control quickly the airborne contaminants levels and assure human in good condition in a sealed chamber This paper describes a trace contaminant control test facility incorporated a 8 m3 sealed environment chamber a regenerative TCCS with P C

Pang, L. P.; Wang, J.; Liu, L. K.; Liu, H.

162

Modeling smog chamber measurements of vehicle exhaust VOC reactivities  

SciTech Connect

Vehicle exhaust VOC reactivities, measured at GM`s smog chamber facility, have been modeled using the SAPRC93 photochemical mechanism. The vehicle exhaust mixtures were generated by a single vehicle run over a portion of the Federal Test Procedure using three Auto/Oil reformulated test gasolines. For each run, up to 156 individual VOC species were identified. Initial HONO concentrations are needed to simulate reactivity measurement runs. (HONO is expected to be generated in a Tedlar bag holding the exhaust sample prior to its transfer to the smog chambers.) Measured and simulated relative incremental reactivities for the three exhaust mixtures are highly consistent. However, measured relative incremental reactivities are more sensitive to fuel effects than simulated ones. The maximum incremental reactivity (MIR)-based relative incremental reactivities, derived from individual species concentrations and MIR factors, are very close to simulated ones. A number of sensitivity simulation runs have been carried out to investigate the impact of HONO and other variables. Results show that relative reactivities of actual vehicle exhaust emissions can be measured by chamber runs in spite of the HONO effect.

Chang, T.Y.; Nance, B.I. [Ford Motor Co., Dearborn, MI (United States). Ford Research Lab.; Kelly, N.A. [General Motors R and D Center, Warren, MI (United States)

1997-12-31

163

EVALUATION OF THE FLUX CHAMBER METHOD FOR MEASURING VOLATILE ORGANIC EMISSIONS FROM SURFACE IMPOUNDMENTS  

EPA Science Inventory

This research deals with the validation of the flux chamber method for measuring volatile organic emissions from liquid surfaces in treatment, storage and disposal facilities (TSDF). A simulated surface impoundment was constructed so that method precision and accuracy could be de...

164

Development of a Rate of Injection Bench and Constant Volume Combustion Chamber for Diesel Spray Diagnostics  

Microsoft Academic Search

To help understand the complex fuel spray combustion phenomena in modern diesel engine using high injection pressure, a fuel injection test bench and a constant volume combustion chamber were developed and demonstrated in this study for diesel spray diagnostics. Both facilities are significant when linking between spray injection and combustion dynamics and engine performance. This link is important to determine

Anthony Phan

2009-01-01

165

The Meditation Chamber: Towards Self-Modulation  

E-print Network

The Meditation Chamber: Towards Self-Modulation Chris Shaw Simon Fraser University, Canada Diane The Meditation Chamber is an immersive virtual environment (VE), initially created to enhance and augment the existing methods of training users how to meditate, and by extension, to realize the benefits from

Shaw, Chris

166

Promoting "Minds-on" Chamber Music Rehearsals  

ERIC Educational Resources Information Center

Chamber music provides myriad opportunities to develop students' ability to think like professional musicians while engaged in the authentic task of working closely with and learning from peers. However, the potential for musical growth inherent in chamber music participation is often unrealized due to either a lack of teacher guidance and support…

Berg, Margaret H.

2008-01-01

167

Studying Phototropism Using a Small Growth Chamber.  

ERIC Educational Resources Information Center

Describes a simple and inexpensive way to construct two small growth chambers for studying phototropism in the science classroom. One chamber is designed to illustrate how plants grow around obstacles to reach light and the other to illustrate directional light responses. (HM)

Fisher, Maryanna, F.; Llewellyn, Gerald C.

1978-01-01

168

ALUMINUM ALLOY VACUUM CHAMBERS FOR SSRF  

Microsoft Academic Search

The antechamber type vacuum system design is chosen in the SSRF storage ring. Each vacuum chamber is machined from two thick plates of A5083-H321 aluminum alloy and welded at their perimeter. The complex structure and the high dimensional precision requirement are the features of these chambers. Some new ideas are adopted in the structure design to decrease the deflection. The

Lixin Yin; Dikui Jiang; Hanwen Du; Xiaoli Jiang

169

The CAST time projection chamber  

NASA Astrophysics Data System (ADS)

One of the three x-ray detectors of the CERN Axion Solar Telescope (CAST) experiment searching for solar axions is a time projection chamber (TPC) with a multi-wire proportional counter (MWPC) as a readout structure. Its design has been optimized to provide high sensitivity to the detection of the low intensity x-ray signal expected in the CAST experiment. A low hardware threshold of 0.8 keV is set to a safe level during normal data taking periods, and the overall efficiency for the detection of photons coming from conversion of solar axions is 62%. Shielding has been installed around the detector, lowering the background level to 4.10 × 10-5 counts cm-2 s-1 keV-1 between 1 and 10 keV. During phase I of the CAST experiment the TPC has provided robust and stable operation, thus contributing with a competitive result to the overall CAST limit on axion photon coupling and mass.

Autiero, D.; Beltrán, B.; Carmona, J. M.; Cebrián, S.; Chesi, E.; Davenport, M.; Delattre, M.; Di Lella, L.; Formenti, F.; Irastorza, I. G.; Gómez, H.; Hasinoff, M.; Lakic, B.; Luzón, G.; Morales, J.; Musa, L.; Ortiz, A.; Placci, A.; Rodrigurez, A.; Ruz, J.; Villar, J. A.; Zioutas, K.

2007-06-01

170

EPA'S HUMAN STUDIES FACILITY AT CHAPEL HILL (BROCHURE)  

EPA Science Inventory

EPA's Human Studies Facility is distiguished by unique, state-of-the art exposure systems designed for studing the health effects of airborne pollutants. The chambers can deliver most gaseous pollutants at precise concentrations and atmospheric conditions. Instrumentation enable...

171

Eighteen months of anterior chamber inflammation.  

PubMed

A 60-year-old Chinese patient was seen multiple times in the ophthalmology outpatient department due to persistent anterior-chamber inflammation and raised intraocular pressure. The patient was being treated with topical corticosteroids and oral acyclovir. Signs of corneal endotheliitis were observed in subsequent follow-ups. A clinical diagnosis could be made on slit-lamp examination, but aetiology could not be specified. An anterior-chamber diagnostic tap performed 18 months after the initial presentation revealed cytomegalovirus (CMV). Prompt response was noted with oral valganciclovir treatment. Our case highlights the importance of performing anterior-chamber tap in cases with persistent anterior-chamber inflammation. There was a long interval between the presentation and diagnosis mainly due to the absence of any concurrent ocular signs. An anterior-chamber tap was delayed until the ocular signs were suggestive of CMV endotheliitis. Timely diagnosis in such cases can improve the outcome as well as the prognosis. PMID:23997088

Jhanji, Vishal; Kwok, Rachel; Young, Alvin L

2013-01-01

172

Aging in large CDF tracking chambers  

NASA Astrophysics Data System (ADS)

The experience of the Collider Detector at Fermilab (CDF) with aging in the large axial drift chamber responsible for tracking in the central region is presented. Premature aging in the Run 1 chamber was observed after only 0.02 C/cm. After cleaning much of the gas system and making modifications to reduce aerosols from the alcohol bubbler, the observed aging rate fell dramatically in test chambers. Considerable effort has been made to better understand the factors that affect aging since the replacement chamber for Run 2 will accumulate about 1.0 C/cm. Current test chambers using the full CDF gas system show aging rates of less than 5%/C/cm.

Binkley, M.; Wagner, R. L.; Mukherjee, A.; Ambrose, D.; Bauer, G.; Khazins, D. M.; Atac, M.

2003-12-01

173

Aging in large CDF tracking chambers  

SciTech Connect

The experience of the Collider Detector at Fermilab (CDF) with aging in the large axial drift chamber responsible for tracking in the central region is presented. Premature aging in the Run 1 chamber was observed after only 0.02 C/cm. After cleaning much of the gas system and making modifications to reduce aerosols from the alcohol bubbler, the observed aging rate fell dramatically in test chambers. Considerable effort has been made to better understand the factors that affect aging since the replacement chamber for Run 2 will accumulate about 1.0 C/cm. Current test chambers using the full CDF gas system show aging rates of less than 5%/C/cm.

M. Binkley et al.

2001-03-19

174

Advanced tube-bundle rocket thrust chamber  

NASA Technical Reports Server (NTRS)

An advanced rocket thrust chamber for future space application is described along with an improved method of fabrication. Potential benefits of the concept are improved cyclic life, reusability, and performance. Performance improvements are anticipated because of the enhanced heat transfer into the coolant which will enable higher chamber pressure in expander cycle engines. Cyclic life, reusability and reliability improvements are anticipated because of the enhanced structural compliance inherent in the construction. The method of construction involves the forming of the combustion chamber with a tube-bundle of high conductivity copper or copper alloy tubes, and the bonding of these tubes by an electroforming operation. Further, the method of fabrication reduces chamber complexity by incorporating manifolds, jackets, and structural stiffeners while having the potential for thrust chamber cost and weight reduction.

Kazaroff, John M.; Pavli, Albert J.

1990-01-01

175

Radar cross section measurements (8-12 GHz) of flat plates painted with microwave absorbing materials  

Microsoft Academic Search

The aim of the present work is to present radar cross section measurements of flat plates painted with radar absorbing material (RAM) in the range of 8-12 GHz. The measurements were carried out in an anechoic chamber at Centro Tecnico Aeroespacial (CTA)-Ministerio da Defesa facilities, and the RAM coating was manufactured at Divisao de Materiais of Instituto de Aeronautica e

M. C. Rezende; I. M. Martin; M. A. S. Miacci; E. L. Nohara

2001-01-01

176

Application of Impedance Loading to Geometric Transition Radar Absorbent Material  

Microsoft Academic Search

This paper describes a novel, lightweight technique for significantly improving the low-frequency reflectivity performance of conventional geometric transition radar absorbent materials as used typically in anechoic chamber facilities for electromagnetic compatibility testing. The improvement is achieved by the inclusion of impedance-loading elements within the base region of the absorber, and these are implemented in the form of one or more

Kenneth Lee Ford; Barry Chambers

2007-01-01

177

The emulsion chamber technology experiment  

NASA Technical Reports Server (NTRS)

Photographic emulsion has the unique property of recording tracks of ionizing particles with a spatial precision of 1 micron, while also being capable of deployment over detector areas of square meters or 10's of square meters. Detectors are passive, their cost to fly in Space is a fraction of that of instruments of similar collecting. A major problem in their continued use has been the labor intensiveness of data retrieval by traditional microscope methods. Two factors changing the acceptability of emulsion technology in space are the astronomical costs of flying large electronic instruments such as ionization calorimeters in Space, and the power and low cost of computers, a small revolution in the laboratory microscope data-taking. Our group at UAH made measurements of the high energy composition and spectra of cosmic rays. The Marshall group has also specialized in space radiation dosimetry. Ionization calorimeters, using alternating layers of lead and photographic emulsion, to measure particle energies up to 10(exp 15) eV were developed. Ten balloon flights were performed with them. No such calorimeters have ever flown in orbit. In the ECT program, a small emulsion chamber was developed and will be flown on the Shuttle mission OAST-2 to resolve the principal technological questions concerning space exposures. These include assessments of: (1) pre-flight and orbital exposure to background radiation, including both self-shielding and secondary particle generation; the practical limit to exposure time in space can then be determined; (2) dynamics of stack to optimize design for launch and weightlessness; and (3) thermal and vacuum constraints on emulsion performance. All these effects are cumulative and affect our ability to perform scientific measurements but cannot be adequately predicted by available methods.

Gregory, John C.

1992-01-01

178

Vapor wall deposition in Teflon chambers  

NASA Astrophysics Data System (ADS)

Teflon chambers are ubiquitous in studies of atmospheric chemistry. Secondary organic aerosol (SOA) formation can be substantially underestimated owing to deposition of SOA-forming compounds to chamber walls. We present here an experimental protocol to constrain the nature of wall deposition of organic vapors in Teflon chambers. We measured the wall deposition rates of 25 oxidized organic compounds generated from the photooxidation of isoprene, toluene, ?-pinene, and dodecane in two chambers that had been extensively used and in two new unused chambers. We found that the extent of prior use of the chamber did not significantly affect the sorption behavior of the Teflon films. The dominant parameter governing the extent of wall deposition of a compound is its wall accommodation coefficient (?w,i), which can be correlated through its volatility (Ci*) with the number of carbons (nC) and oxygens (nO) in the molecule. Among the 25 compounds studied, the maximum wall deposition rate is approached by the most highly oxygenated and least volatile compounds. The extent to which vapor wall deposition impacts measured SOA yields depends on the competition between uptake of organic vapors by suspended particles and chamber walls. Gas-particle equilibrium partitioning is established relatively rapidly in the presence of perfect accommodation of organic vapors onto particles or when a sufficiently large concentration of suspended particles is present. The timescale associated with vapor wall deposition can vary from minutes to hours depending on the value of ?w,i. For volatile and intermediate volatility organic compounds (small ?w,i), gas-particle partitioning will be dominant for typical particle number concentrations in chamber experiments. For large ?w,i, vapor transport to particles is suppressed by competition with the chamber walls even with perfect particle accommodation.

Zhang, X.; Schwantes, R. H.; McVay, R. C.; Lignell, H.; Coggon, M. M.; Flagan, R. C.; Seinfeld, J. H.

2014-10-01

179

Gas Electron Multiplier (GEM) Chamber Characteristics Test  

SciTech Connect

Gas Electron Multipliers (GEMs) have been used in many HEP experiments as tracking detectors. They are sensitive to X-rays which allows use beyond that of HEP. The UTA High Energy group has been working on using GEMs as the sensitive gap detector in a DHCAL for the ILC. The physics goals at the ILC put a stringent requirement on detector performance. Especially the precision required for jet mass and positions demands an unprecedented jet energy resolution to hadronic calorimeters. A solution to meet this requirement is using the Particle Flow Algorithm (PFA). In order for PFA to work well, high calorimeter granularity is necessary. Previous studies based on GEANT simulations using GEM DHCAL gave confidence on the performance of GEM in the sensitive gap in a sampling calorimeter and its use as a DHCAL in PFA. The UTA HEP team has built several GEM prototype chambers, including the current 30cm x 30cm chamber integrated with the SLAC-developed 64 channel kPiX analog readout chip. This chamber has been tested on the bench using radioactive sources and cosmic ray muons. In order to have fuller understanding of various chamber characteristics, the experiments plan to expose 1-3 GEM chambers of dimension 35cm x 35cm x 5cm with 1cm x 1cm pad granularity with 64 channel 2-D simultaneous readout using the kPiX chip. In this experiment the experiments pan to measure MiP signal height, chamber absolute efficiencies, chamber gain versus high voltage across the GEM gap, the uniformity of the chamber across the 8cm x 8cm area, cross talk and its distance dependence to the triggered pad, chamber rate capabilities, and the maximum pad occupancy rate.

Yu, Jaehoon; White, Andy; Park, Seongtae; Hahn, Changhie; Baldeloma, Edwin; Tran, Nam; McIntire, Austin; /Texas U., Arlington; Soha, Aria; /Fermilab

2011-01-11

180

Mechanical construction techniques for assembling wire chambers  

SciTech Connect

This report is composed of the results of many experiments with multi-wire proportional chambers (MWPCs), particularly those built within N-2. All of the assembly construction techniques I discuss have been experimentally evaluated and found to be useful. Although most of these techniques were developed to answer specific problems with the N-2 chamber, many of them are equally applicable to similar designs. This text is intended for the individual who is troubleshooting actual chambers; I have included some MWPC design information and some detector comparisons, but neither of these is covered in detail here. 15 refs., 25 figs., 3 tabs.

MacArthur, D.W.

1991-07-01

181

Characterization of electromagnetic fields in an extended chamber at the Short Pulse Experimental Electron Device (SPEED) simulator  

Microsoft Academic Search

The electromagnetic (EM) fields present during testing in a large vacuum chamber at the Short Pulse Experimental Electron Device (SPEED) facility are observed and measured using B-dot and D-dot detectors. Because the cathode of the vacuum diode is exposed to the chamber, the EM fields are significant and could adversely affect nonfaraday-shielded experiments. The differential magnetic fields and electric fields

Kenneth K. Hunt

1993-01-01

182

HYLIFE-II reactor chamber design refinements  

SciTech Connect

Mechanical design features of the reactor chamber for the HYLIFE-II inertial confinement fusion power plant are presented. A combination of oscillating and steady, molten salt streams (Li{sub 2}BeF{sub 4}) are used for shielding and blast protection of the chamber walls. The system is designed for a 6 Hz repetition rate. Beam path clearing, between shots, is accomplished with the oscillating flow. The mechanism for generating the oscillating streams is described. A design configuration of the vessel wall allows adequate cooling and provides extra shielding to reduce thermal stresses to tolerable levels. The bottom portion of the reactor chamber is designed to minimize splash back of the high velocity (>12 m/s) salt streams and also recover up to half of the dynamic head. Cost estimates for a 1 GWe and 2 GWe reactor chamber are presented.

House, P.A.

1994-06-01

183

Formation mechanisms of combustion chamber deposits  

E-print Network

Combustion chamber deposits are found in virtually all internal combustion engines after a few hundred hours of operation. Deposits form on cylinder, piston, and head surfaces that are in contact with fuel-air mixture ...

O'Brien, Christopher J. (Christopher John)

2001-01-01

184

Developing cloud chambers with high school students  

E-print Network

The result and outcome of the cloud chamber project, which aims to develop a cloud chamber useful for science education is reported in detail. A project includes both three high school students and a teacher as a part of Super Science High School (SSH) program in our school. We develop a dry ice free cloud chamber using salt and ice (or snow). Technical detail of the chamber is presented. We also argue how the project affects student's cognition, motivation, academic skills and behavior. The research project had been done in very similar way to those of professional researchers, i.e., planning research, applying fund, writing a paper and giving a talk in conferences. From interviews with students, we learn that such style of scientific activity is very effective in promoting student's motivation for learning science.

Ishizuka, Ryo; Sato, Shoma; Zeze, Syoji

2013-01-01

185

21 CFR 868.5470 - Hyperbaric chamber.  

Code of Federal Regulations, 2010 CFR

...the movement of oxygen from the environment to a patient's tissue by means of pressurization that is greater than atmospheric pressure. This device does not include topical oxygen chambers for extremities (§ 878.5650). (b)...

2010-04-01

186

User Manual for LLNL's 24 Chamber Instrument.  

National Technical Information Service (NTIS)

The 24 chamber instrument, called the PolyHanaa, is designed to perform rapid, real-time detection of biological agents using the Polymerase Chain Reaction (PCR) process. Liquid samples are pipetted into small, disposable polypropylene inserts which are p...

J. Richards

2001-01-01

187

EFFECT OF DIETHYLHYDROXYLAMINE ON SMOG CHAMBER IRRADIATIONS  

EPA Science Inventory

The addition of diethylhydroxylamine (DEHA) to the urban atmosphere had been suggested as a means of preventing photochemical smog. Smog chamber studies were carried out to investigate the photochemical smog formation characteristics of irradiated hydrocarbon-nitrogen oxides - DE...

188

Studies of Helium Based Gas Mixtures Using a Small Cell Drift Chamber  

SciTech Connect

An international collaboration is currently working on the construction and design of an asymmetric B Factory at the Stanford Linear Accelerator Center that will be ready to collect data in 1999. The main physics motivation for such a facility is to test the description and mechanism of CP violation in the Standard Model of particle physics and provide insight into the question of why more matter than antimatter is observed in the universe today. In particular, this experiment will measure CP violation in the decay of B mesons. In the early stages of this effort, the Canadian contingent proposed to build the central tracking chamber for the BaBar detector. Presently, a prototype drift chamber is in operation and studies are being performed to test some of the unique features of drift chamber design dictated by the conditions of the experiment. Using cosmic muons, it is possible to study tracking and pattern recognition in the prototype chamber, and therefore calculate the efficiency and spatial resolution of the prototype chamber cells. These performance features will be used to test whether or not the helium-based gas mixtures proposed for the BaBar drift chamber are a viable alternative to the more traditional argon-based gases.

Heise, Jaret; /British Columbia U.

2006-07-07

189

Calibration of the borated ion chamber at NIST reactor thermal column.  

PubMed

In boron neutron capture therapy and boron neutron capture enhanced fast neutron therapy, the absorbed dose of tissue due to the boron neutron capture reaction is difficult to measure directly. This dose can be computed from the measured thermal neutron fluence rate and the (10)B concentration at the site of interest. A borated tissue-equivalent (TE) ion chamber can be used to directly measure the boron dose in a phantom under irradiation by a neutron beam. Fermilab has two Exradin 0.5 cm(3) Spokas thimble TE ion chambers, one loaded with boron, available for such measurements. At the Fermilab Neutron Therapy Facility, these ion chambers are generally used with air as the filling gas. Since alpha particles and lithium ions from the (10)B(n,alpha)(7)Li reactions have very short ranges in air, the Bragg-Gray principle may not be satisfied for the borated TE ion chamber. A calibration method is described in this paper for the determination of boron capture dose using paired ion chambers. The two TE ion chambers were calibrated in the thermal column of the National Institute of Standards and Technology (NIST) research reactor. The borated TE ion chamber is loaded with 1,000 ppm of natural boron (184 ppm of (10)B). The NIST thermal column has a cadmium ratio of greater than 400 as determined by gold activation. The thermal neutron fluence rate during the calibration was determined using a NIST fission chamber to an accuracy of 5.1%. The chambers were calibrated at two different thermal neutron fluence rates: 5.11 x 10(6) and 4.46 x 10(7)n cm(-2) s(-1). The non-borated ion chamber reading was used to subtract collected charge not due to boron neutron capture reactions. An optically thick lithium slab was used to attenuate the thermal neutrons from the neutron beam port so the responses of the chambers could be corrected for fast neutrons and gamma rays in the beam. The calibration factor of the borated ion chamber was determined to be 1.83 x 10(9) +/- 5.5% (+/- 1sigma) n cm(-2) per nC at standard temperature and pressure condition. PMID:17525059

Wang, Z; Hertel, N E; Lennox, A

2007-01-01

190

Numerical simulation of magma chamber dynamics.  

NASA Astrophysics Data System (ADS)

Magma chambers are characterized by periodic arrivals of deep magma batches that give origin to complex patterns of magma convection and mixing, and modify the distribution of physical quantities inside the chamber. We simulate the transient, 2D, multi-component homogeneous dynamics in geometrically complex dyke+chamber systems, by means of GALES, a finite element parallel C++ code solving mass, momentum and energy equations for multi-component homogeneous gas-liquid (± crystals) mixtures in compressible-to-incompressible flow conditions. Code validation analysis includes several cases from the classical engineering literature, corresponding to a variety of subsonic to supersonic gas-liquid flow regimes (see http://www.pi.ingv.it/~longo/gales/gales.html). The model allows specification of the composition of the different magmas in the domain, in terms of ten major oxides plus the two volatile species H2O and CO2. Gas-liquid thermodynamics are modeled by using the compositional dependent, non-ideal model in Papale et al. (Chem.. Geol., 2006). Magma properties are defined in terms of local pressure, temperature, and composition including volatiles. Several applications are performed within domains characterized by the presence of one or more magma chambers and one or more dykes, with different geometries and characteristic size from hundreds of m to several km. In most simulations an initial compositional interface is placed at the top of a feeding dyke, or at larger depth, with the deeper magma having a lower density as a consequence of larger volatile content. The numerical results show complex patterns of magma refilling in the chamber, with alternating phases of magma ingression and magma sinking from the chamber into the feeding dyke. Intense mixing takes place in feeding dykes, so that the new magma entering the chamber is always a mixture of the deep and the initially resident magma. Buoyant plume rise occurs through the formation of complex convective patterns, giving origin to a density-stratified magma chamber.

Longo, Antonella; Papale, Paolo; Montagna, Chiara Paola; Vassalli, Melissa; Giudice, Salvatore; Cassioli, Andrea

2010-05-01

191

Thermal environmental tests on space simulation chamber  

Microsoft Academic Search

Thermal testing of space payloads at Sandia National Laboratories is conducted in a large cylindrical (7.0 feet in diameter) vacuum chamber with temperature controlled walls. The payload is generally attached to a baseplate with independent temperature controls. To establish well-defined boundary conditions during the tests, uniform wall temperatures are desired in the test chamber. Thermal-vacuum tests were conducted on this

R. L. Akau; J. P. Freshour; S. L. Wilde

1989-01-01

192

Tracking with wire chambers at the SSC  

SciTech Connect

Limitations placed on wire chambers by radiation damage and rate requirements in the SSC environment are reviewed. Possible conceptual designs for wire chamber tacking systems that meet these requirements are discussed. Computer simulation studies of tracking in such systems are presented. Simulations of events from interesting physics at the SSC, including hits from minimum bias background events, are examined. Results of some preliminary pattern recognition studies are given. 13 refs., 11 fig., 1 tab.

Hanson, G.G.; Gundy, M.C.; Palounek, A.P.T.

1989-07-01

193

Signal shapes in a TPC wire chamber  

NASA Astrophysics Data System (ADS)

We study signal shapes in Multi Wire Proportional Chambers (MWPCs) and the influence of the electron distribution around the wire on the ion tail characteristics. Simulations of the ion tail for two different geometries, different voltages and therefore gas gains were performed. These simulations are compared to measurements carried out with the ALICE TPC wire chambers for a Ne/CO 2/N 2 gas mixture, which allows to extract the avalanche spread around the anode wires of the MWPC.

Rossegger, S.; Riegler, W.

2010-11-01

194

Cloud chamber visualization of primary cosmic rays  

SciTech Connect

From 1948 until 1963, cloud chambers were carried to the top of the atmosphere by balloons. From these flights, which were begun by Edward P. Ney at the University of Minnesota, came the following results: discovery of heavy cosmic ray nuclei, development of scintillation and cherenkov detectors, discovery of cosmic ray electrons, and studies of solar proton events. The history of that era is illustrated here by cloud chamber photographs of primary cosmic rays.

Earl, James A. [Department of Astronomy, University of Maryland, College Park MD (United States)

2013-02-07

195

Outdoor chamber study to test multi-day effects. Volume 3. Documentation for computer-readable environmental chamber data. Final report, August 1982-August 1984  

SciTech Connect

The smog chamber facilities of the University of California, Riverside were used to collect experimental data to assess the effects of multi-day irradiations on photochemical oxidant formation. This volume includes documentation on the computer-readable magnetic tape that contains all the data collected in the study. The tape is suitable for use by modelers to develop and test kinetic mechanisms of photochemical smog formation.

Carter, W.P.L.; Dodd, M.C.; Long, W.D.; Atkinson, R.

1984-12-01

196

Analysis and simulation of the process of medicobiological waste treatment in a plasma chamber incinerator  

NASA Astrophysics Data System (ADS)

Analysis of the composition and the degree of toxicity of medicobiological wastes has been performed with the use of the results of investigations made in different countries. It has been shown that such wastes are highly hazardous to ecology and a universal technology of their management is needed. We have developed and tested a plasma chamber incinerator for plasmothermal treatment of medicobiological waste. To optimize the operating conditions of the facility and prevent chemical and thermal pollution of the environment, we have constructed a model of thermal calculation of the plasma chamber incinerator.

Mossé, A. L.; Savchin, V. V.

2006-07-01

197

A TPC (Time Projection Chamber) detector for the study of high multiplicity heavy ion collisions  

SciTech Connect

The design of a Time Projection Chamber (TPC) detector with complete pad coverage is presented. The TPC will allow the measurements of high multiplicity ({approx} 200 tracks) relativistic nucleus-nucleus collisions initiated with the heaviest, most energetic projectiles available at the LBL BEVALAC accelerator facility. The front end electronics, composed of over 15,000 time sampling channels, will be located on the chamber. The highly integrated, custom designed, electronics and the VME based data acquisition system are described. 10 refs., 8 figs., 1 tab.

Rai, G.; Arthur, A.; Bieser, F.; Harnden, C.W.; Jones, R.; Klienfelder, S.; Lee, K.; Matis, H.S.; Nakamura, M.; McParland, C.; Nesbitt, D.; Odyniec, G.; Olson, D.; Pugh, H.G.; Ritter, H.G.; Symons, T.J.M.; Wieman, H.; Wright, M.; Wright, R. (Lawrence Berkeley Lab., CA (USA)); Rudge, A. (California Univ., Davis, CA (USA))

1990-01-01

198

IFE thick liquid wall chamber dynamics: Governing mechanisms andmodeling and experimental capabilities  

SciTech Connect

For thick liquid wall concepts, it is important to understand the different mechanisms affecting the chamber dynamics and the state of the chamber prior to each shot a compared with requirements from the driver and target. These include ablation mechanisms, vapor transport and control, possible aerosol formation, as well as protective jet behavior. This paper was motivated by a town meeting on this subject which helped identify the major issues, assess the latest results, review the capabilities of existing modeling and experimental facilities with respect to addressing remaining issues, and helping guide future analysis and R&D efforts; the paper covers these exact points.

Raffray, A.R.; Meier, W.; Abdel-Khalik, S.; Bonazza, R.; Calderoni, P.; Debonnel, C.S.; Dragojlovic, Z.; El-Guebaly, L.; Haynes,D.; Latkowski, J.; Olson, C.; Peterson, P.F.; Reyes, S.; Sharpe, P.; Tillack, M.S.; Zaghloul, M.

2005-01-24

199

High-pressure promoted combustion chamber  

NASA Technical Reports Server (NTRS)

In the preferred embodiment of the promoted combusiton chamber disclosed herein, a thick-walled tubular body that is capable of withstanding extreme pressures is arranged with removable upper and lower end closures to provide access to the chamber for dependently supporting a test sample of a material being evaluated in the chamber. To facilitate the real-time analysis of a test sample, several pressure-tight viewing ports capable of withstanding the simulated environmental conditions are arranged in the walls of the tubular body for observing the test sample during the course of the test. A replaceable heat-resistant tubular member and replaceable flame-resistant internal liners are arranged to be fitted inside of the chamber for protecting the interior wall surfaces of the combustion chamber during the evaluation tests. Inlet and outlet ports are provided for admitting high-pressure gases into the chamber as needed for performing dynamic analyses of the test sample during the course of an evaluation test.

Rucker, Michelle A. (inventor); Stoltzfus, Joel M. (inventor)

1991-01-01

200

Development of sputtered techniques for thrust chambers  

NASA Technical Reports Server (NTRS)

Techniques and materials were developed and evaluated for the fabrication and coating of advanced, long life, regeneratively cooled thrust chambers. Materials were analyzed as fillers for sputter application of OFHC copper as a closeout layer to channeled inner structures; of the materials evaluated, aluminum was found to provide the highest bond strength and to be the most desirable for chamber fabrication. The structures and properties were investigated of thick sputtered OFHC copper, 0.15 Zr-Cu, Al2O3,-Cu, and SiC-Cu. Layered structures of OFHC copper and 0.15 Zr-Cu were investigated as means of improving chamber inner wall fatigue life. The evaluation of sputtered Ti-5Al-2.5Sn, NASA IIb-11, aluminum and Al2O3-Al alloys as high strength chamber outer jackets was performed. Techniques for refurbishing degraded thrust chambers with OFHC copper and coating thrust chambers with protective ZrO2 and graded ZrO2-copper thermal barrier coatings were developed.

Mullaly, J. R.; Hecht, R. J.; Schmid, T. E.; Torrey, C. T.

1975-01-01

201

Liquid-filled ionization chamber temperature dependence  

NASA Astrophysics Data System (ADS)

Temperature and pressure corrections of the read-out signal of ionization chambers have a crucial importance in order to perform high-precision absolute dose measurements. In the present work the temperature and pressure dependences of a sealed liquid isooctane filled ionization chamber (previously developed by the authors) for radiotherapy applications have been studied. We have analyzed the thermal response of the liquid ionization chamber in a ˜20C interval around room temperature. The temperature dependence of the signal can be considered linear, with a slope that depends on the chamber collection electric field. For example, a relative signal slope of 0.27×10-2 K-1 for an operation electric field of 1.67×106 V m-1 has been measured in our detector. On the other hand, ambient pressure dependence has been found negligible, as expected for liquid-filled chambers. The thermal dependence of the liquid ionization chamber signal can be parametrized within the Onsager theory on initial recombination. Considering that changes with temperature of the detector response are due to variations in the free ion yield, a parametrization of this dependence has been obtained. There is a good agreement between the experimental data and the theoretical model from the Onsager framework.

Franco, L.; Gómez, F.; Iglesias, A.; Pardo, J.; Pazos, A.; Pena, J.; Zapata, M.

2006-05-01

202

Expandable Purge Chambers Would Protect Cryogenic Fittings  

NASA Technical Reports Server (NTRS)

Expandable ice-prevention and cleanliness-preservation (EIP-CP) chambers have been proposed to prevent the accumulation of ice or airborne particles on quick-disconnect (QD) fittings, or on ducts or tubes that contain cryogenic fluids. In the original application for which the EIP-CP chambers were conceived, there is a requirement to be able to disconnect and reconnect the QD fittings in rapid succession. If ice were to form on the fittings by condensation and freezing of airborne water vapor on the cold fitting surfaces, the ice could interfere with proper mating of the fittings, making it necessary to wait an unacceptably long time for the ice to thaw before attempting reconnection. By keeping water vapor away from the cold fitting surfaces, the EIP-CP chambers would prevent accumulation of ice, preserving the ability to reconnect as soon as required. Basically, the role of an EIP-CP chamber would be to serve as an enclosure for a flow of dry nitrogen gas that would keep ambient air away from QD cryogenic fittings. An EIP-CP chamber would be an inflatable device made of a fabriclike material. The chamber would be attached to an umbilical plate holding a cryogenic QD fitting.

Townsend, Ivan I., III

2004-01-01

203

Quality control of ATLAS muon chambers  

E-print Network

ATLAS is a general-purpose experiment for the future Large Hadron Collider (LHC) at CERN. Its Muon Spectrometer will require ? 5500m2 of precision tracking chambers to measure the muon tracks along a spectrometer arm of 5m to 15m length, embedded in a magnetic field of ? 0.5T. The precision tracking devices in the Muon System will be high pressure drift tubes (MDTs). Approximately 370,000 MDTs will be assembled into ? 1200 drift chambers. The performance of the MDT chambers is very much dependent on the mechanical quality of the chambers. The uniformity and stability of the performance can only be assured providing very high quality control during production. Gas tightness, high-voltage behaviour and dark currents are global parameters which are common to gas detectors. For all chambers, they will be tested immediately after the chamber assembly at every production site. Functional tests, for example radioactive source scans and cosmic-ray runs, will be performed in order to establish detailed performan...

Fabich, Adrian

204

Cyclic fatigue analysis of rocket thrust chambers. Volume 1: OFHC copper chamber low cycle fatigue  

NASA Technical Reports Server (NTRS)

A three-dimensional finite element elasto-plastic strain analysis was performed for the throat section of a regeneratively cooled rocket combustion chamber. The analysis employed the RETSCP finite element computer program. The analysis included thermal and pressure loads, and the effects of temperature dependent material properties, to determine the strain range corresponding to the chamber operating cycle. The analysis was performed for chamber configuration and operating conditions corresponding to a hydrogen-oxygen combustion chamber which was fatigue tested to failure. The computed strain range at typical chamber operating conditions was used in conjunction with oxygen-free, high-conductivity (OHFC) copper isothermal fatigue test data to predict chamber low-cycle fatigue life.

Miller, R. W.

1974-01-01

205

12. View north of Tropic Chamber. Natick Research & ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

12. View north of Tropic Chamber. - Natick Research & Development Laboratories, Climatic Chambers Building, U.S. Army Natick Research, Development & Engineering Center (NRDEC), Natick, Middlesex County, MA

206

13. View south of Arctic Chamber. Natick Research & ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

13. View south of Arctic Chamber. - Natick Research & Development Laboratories, Climatic Chambers Building, U.S. Army Natick Research, Development & Engineering Center (NRDEC), Natick, Middlesex County, MA

207

TEMPERATURE GRADIENT CHAMBERS FOR RESEARCH ON GLOBAL ENVIRONMENT CHANGE. I. THERMAL ENVIRONMENT IN A LARGE CHAMBER  

Microsoft Academic Search

OKADA M. HAMASAKI T. and HAYASH! T. Temperature gradient chambers for research on global environment change. I. Thermal environment in a large chamber. BIOTRONICS 24, 85-97, 1995. Simple and low-cost temperature gradient chambers (TGC) have been developed to study the effects of temperature on field crops. Providing a continuous one-way air flow along the long axis of the TGC, the

M. OKADA; T. HAMASAKI; T. HAYASHI

208

Characterization and testing of a new environmental chamber designed for emission aging studies  

NASA Astrophysics Data System (ADS)

A 29 m3 Teflon chamber, designed for aging studies of combustion aerosols, at the University of Eastern Finland is described and characterized. The chamber belongs to a research facility, called Ilmari, where small-scale combustion devices, a dynamometer for vehicle exhaust studies, dilution systems, the chamber, as well as cell and animal exposure devices are side by side under the same roof. The small surface-to-volume ratio of the chamber enables reasonably long experiment times, with particle wall loss rate constants of 0.088, 0.080, 0.045, and 0.040 h-1 for polydisperse, 50, 100, and 200 nm monodisperse aerosols, respectively. The NO2 photolysis rate can be adjusted from zero to 0.62 min-1. The irradiance spectrum is centered at 365 nm and the maximum irradiance, produced by 160 blacklight lamps, is 29.7 W m-2, which corresponds to the UV irradiance in Central Finland at noon on a sunny day in the midsummer. The temperature inside the chamber is uniform and can be kept at 25 ± 1 °C when half of the blacklights are on. The chamber is kept in an overpressure with a moving top frame, which prevents sample dilution and contamination from entering the chamber during an experiment. The functionality of the chamber was tested with oxidation experiments of toluene, resulting in secondary organic aerosol (SOA) yields of 33-44%, depending on the initial conditions, such as the NOx concentration. The highest gaseous oxidation product yields of 14.4-19.5% were detected with ions corresponding to 2-butenedial (m/z 73.029) and 4-oxo-2-pentenal (m/z 99.044). Overall, reasonable yields of SOA and gaseous reaction products, comparable to those obtained in other laboratories, were obtained.

Leskinen, A.; Yli-Pirilä, P.; Kuuspalo, K.; Sippula, O.; Jalava, P.; Hirvonen, M.-R.; Jokiniemi, J.; Virtanen, A.; Komppula, M.; Lehtinen, K. E. J.

2014-06-01

209

LABORATORY ANIMAL FACILITIES STANDARD OPERATING PROCEDURE  

E-print Network

Faculty, students, and technicians who work with live animals in their labs or testing rooms. 2.0 Procedure 2.1 All equipment, transfer boxes, and holding/testing chambers used for animal research1.C.7 LABORATORY ANIMAL FACILITIES STANDARD OPERATING PROCEDURE FOR SANITATION OF RESEARCH

Krovi, Venkat

210

Focal Point Inside the Vacuum Chamber for Solar Thermal Propulsion  

NASA Technical Reports Server (NTRS)

Researchers at the Marshall Space Flight Center (MSFC) have designed, fabricated, and tested the first solar thermal engine, a non-chemical rocket engine that produces lower thrust but has better thrust efficiency than a chemical combustion engine. MSFC turned to solar thermal propulsion in the early 1990s due to its simplicity, safety, low cost, and commonality with other propulsion systems. Solar thermal propulsion works by acquiring and redirecting solar energy to heat a propellant. The 20- by 24-ft heliostat mirror (not shown in this photograph) has dual-axis control that keeps a reflection of the sunlight on an 18-ft diameter concentrator mirror, which then focuses the sunlight to a 4-in focal point inside the vacuum chamber. The focal point has 10 kilowatts of intense solar power. This photograph is a close-up view of a 4-in focal point inside the vacuum chamber at the MSFC Solar Thermal Propulsion Test facility. As part of MSFC's Space Transportation Directorate, the Propulsion Research Center serves as a national resource for research of advanced, revolutionary propulsion technologies. The mission is to move the Nation's capabilities beyond the confines of conventional chemical propulsion into an era of aircraft-like access to Earth orbit, rapid travel throughout the solar system, and exploration of interstellar space.

1999-01-01

211

Stability of A-150 plastic ionization chamber response over a ~30 year period  

SciTech Connect

At the NIU Institute for Neutron Therapy at Fermilab, the clinical tissue-equivalent ionization chamber response is measured every treatment day using a cesium source that was configured to match readings obtained at the National Bureau of Standards. Daily measurements are performed in air using the air-to-tissue dose conversion factors given in AAPM Report no. 7. The measured exposure calibration factors have been tabulated and graphed as a function of time from 1978 to present. For A-150 plastic ionization chambers, these factors exhibit a sinusoidal variation with a period of approximately one year and amplitude of {+-} 1%. This variation, attributable to the hygroscopic nature of A-150 plastic, is correlated with the relative humidity of the facility, and is greater than the humidity corrections for gas described in the literature. Our data suggest that chamber calibration should be performed at least weekly to accommodate these variations.

Kroc, Thomas K.; Lennox, Arlene J.; /Fermilab

2007-08-01

212

Behavior of a Radial Time Projection Chamber  

NASA Astrophysics Data System (ADS)

Using Gas Electron Multiplying (GEM) foils for amplification, the detector allows for three-dimensional representations of particle tracks through two half cylinders filled with gas. Developed for the Bound Nucleon Structure (BONUS) experiment at Jefferson Lab, the RTPC allows experimenters to study the quark composition of the neutron by scattering electrons from deuterium nuclei. The defining feature of the detector is that it allows for a complete view of the interaction of the electron and target gas, including the protons left over after a reaction on the neutron. This experiment seeks to understand the efficiency of the detector and its amplification (signal strength for a given ionization, as a function of detector gas and high voltage), by making a measurement of the amount of energy deposited in the chamber per unit length from cosmic radiation. In order to test each half of the Radial Time Projection Chamber we use an 85% Helium and 15% Dimethyl Ether (85/15 HeDME) and an 80/20 HeDME at optimal voltages to detect cosmic particles. The detector takes an electronic snapshot of the incident particle by examining the charge deposited as a function of time. The importance of this technology should not be underestimated. Radial Time Projection Chambers could, in some applications, replace current Time Projection Chambers and Wire Chambers.

Bradshaw, Peter

2006-10-01

213

Design characteristics of a heat pipe test chamber  

NASA Technical Reports Server (NTRS)

LeRC has designed a heat pipe test facility which will be used to provide data for validating heat pipe computer codes. A heat pipe test chamber that uses helium gas for enhancing heat transfer was investigated. The conceptual design employs the technique of guarded heating and guarded cooling to facilitate accurate measurements of heat transfer rates to the evaporator and from the condenser. The design parameters are selected for a baseline heat pipe made of stainless steel with an inner diameter of 38.10 mm and a wall thickness of 1.016 mm. The heat pipe operates at a design temperature of 1000 K with an evaporator radial heat flux of 53 W/sq. cm.

Baker, Karl W.; Jang, J. Hoon; Yu, Juin S.

1992-01-01

214

Developing a fast ionization chamber for transfer reaction studies  

NASA Astrophysics Data System (ADS)

Detection of beam and beam like recoils at far forward angles is often critical for radioactive beam measurements in inverse kinematics. Gas-filled ionization chambers are well suited for these applications, since they have moderately good energy resolution and can take prolonged exposure to beam compared to fragile semiconductor detectors. Conventional ion counters using a Frisch grid, however, have slow response times because the ionized electrons must travel long distances to the anodes. To reduce response times, a fast ion counter using a tilted window and tilted electrodes was developed and tested at ORNL's Holifield Radioactive Ion Beam Facility, modified from an original design by Kimura et al. [1]. The maximum counting rate and energy resolution, along with future plans for using the new ion counter, will be presented. [4pt] [1] K. Kimura et al., Nucl. Inst. Meth. Phys. Res. A 538, 608 (2005).

Chae, K. Y.; Bardayan, D. W.; Smith, M. S.; Schmitt, K. T.; Ahn, S. H.; Peters, W. A.; Strauss, S.

2011-10-01

215

The construction of the KLOE drift chamber: Present status KLOE Drift Chamber Group  

NASA Astrophysics Data System (ADS)

The status of the construction of the KLOE Drift Chamber is reviewed. With its 4 m diameter, it will be the biggest drift chamber ever built. The stringing of 52 000 wires is a titanic effort: details are given about the semiautomatic system, the quality tests on wires and the monitoring of end-plates deformations.

Valente, Paolo; Andryakov, A.; Antonelli, A.; Baldini-Ferroli, R.; Bencivenni, G.; Bucci, L.; Calcaterra, A.; Campana, P. L.; Dell'Agnello, S.; de Sangro, R.; De Simone, P.; Felici, G.; Finocchiaro, G.; Forti, C.; Moccia, S.; Passalacqua, L.; Patera, V.; Piccolo, M.; Kulikov, V.; Nedosekin, A.; Cataldi, G.; Denig, A.; Kluge, W.; Von Hagel, U.; Weseler, S.; Elia, V.; Golovatyuk, V.; Gorini, E.; Grancagnolo, F.; Panareo, M.; Primavera, M.; Spagnolo, S.; De Lucia, E.; Lacava, F.; Luisi, C.; Picca, D.; Pontecorvo, L.; Messi, R.; Paoluzi, L.; Valente, P.; Bacci, C.; Ceradini, F.

216

Final report for NIF chamber dynamics studies, final rept (May 1997), Subcontract No. B291847  

SciTech Connect

The National Ignition Facility (NIF), a 1.8 MJ, 192 laser beam facility, will have anticipated fusion yields of up to 20 MJ from D-T pellets encased in a gold hohlraum target. The energy emitted from the target in the form of x rays, neutrons, target debris kinetic energy, and target shrapnel will be contained in a 5 m. radius spherical target chamber. Various diagnostics will be stationed around the target at varying distances from the target. During each shot, the target will emit x rays that will vaporize nearby target facing surfaces including those of the diagnostics, the target positioner, and other chamber structures. This ablated vapor will be transported throughout the chamber, and will eventually condense and deposit on surfaces in the chamber, including the final optics debris shields. The research at the University of California at Berkeley relates primarily to the NIF chamber dynamics. The key design issues are the ablation of the chamber structures, transport of the vapor through the chamber and the condensation or deposition processes of those vaporized materials. An understanding of these processes is essential in developing a concept for protecting the final optics debris shields from an excessive coating (> 10 {Angstrom}) of target debris and ablated material, thereby prolonging their lifetime between change- outs. At Berkeley, we have studied the physical issues of the ablation process and the effects of varying materials, the condensation process of the vaporized material, and design schemes that can lower the threat posed to the debris shields by these processes. In addition to the work described briefly above, we performed extensive analysis of the target-chamber thermal response to in- chamber CO{sub 2} Cleaning and of work performed to model the behavior of silica vapor. The work completed this year has been published in several papers and a dissertation [1-6]. This report provides a summary of the work completed this year, as well as copies fo presentation materials that have not been published elsewhere. In particular, the Appendix contains copies of presentations made on CO{sub 2} cleaning that are not available elsewhere.

Peterson, P.F.; Jin, H.; Scott, J.M. [University of California, Berkeley (United States)

1997-07-01

217

High temperature thrust chamber for spacecraft  

NASA Technical Reports Server (NTRS)

A high temperature thrust chamber for spacecraft (20) is provided herein. The high temperature thrust chamber comprises a hollow body member (12) having an outer surface and an internal surface (16) defining the high temperature chamber (10). The body member (12) is made substantially of rhenium. An alloy (18) consisting of iridium and at least alloying metal selected of the group consisting of rhodium, platinum and palladium is deposited on at least a portion of the internal surface (16) of the body member (12). The iridium and the alloying metal are electrodeposited onto the body member (12). A HIP cycle is performed upon the body member (12) to cause the coating of iridium and the alloying metal to form the alloy (18) which protects the body member (12) from oxidation.

Chazen, Melvin L. (Inventor); Mueller, Thomas J. (Inventor); Kruse, William D. (Inventor)

1998-01-01

218

Chamber LIDAR measurements of aerosolized biological simulants  

NASA Astrophysics Data System (ADS)

A chamber aerosol LIDAR is being developed to perform well-controlled tests of optical scattering characteristics of biological aerosols, including Bacillus atrophaeus (BG) and Bacillus thuringiensis (BT), for validation of optical scattering models. The 1.064 ?m, sub-nanosecond pulse LIDAR allows sub-meter measurement resolution of particle depolarization ratio or backscattering cross-section at a 1 kHz repetition rate. Automated data acquisition provides the capability for real-time analysis or recording. Tests administered within the refereed 1 cubic meter chamber can provide high quality near-field backscatter measurements devoid of interference from entrance and exit window reflections. Initial chamber measurements of BG depolarization ratio are presented.

Brown, David M.; Thrush, Evan P.; Thomas, Michael E.; Siegrist, Karen M.; Baldwin, Kevin; Quizon, Jason; Carter, Christopher C.

2009-05-01

219

Temperature dependent BRDF facility  

NASA Astrophysics Data System (ADS)

Applications involving space based instrumentation and aerodynamically heated surfaces often require knowledge of the bi-directional reflectance distribution function (BRDF) of an exposed surface at high temperature. Addressing this need, the Johns Hopkins University Applied Physics Laboratory (JHU/APL) developed a BRDF facility that features a multiple-port vacuum chamber, multiple laser sources covering the spectral range from the longwave infrared to the ultraviolet, imaging pyrometry and laser heated samples. Laser heating eliminates stray light that would otherwise be seen from a furnace and requires minimal sample support structure, allowing low thermal conduction loss to be obtained, which is especially important at high temperatures. The goal is to measure the BRDF of ceramic-coated surfaces at temperatures in excess of 1000°C in a low background environment. Most ceramic samples are near blackbody in the longwave infrared, thus pyrometry using a LWIR camera can be very effective and accurate.

Airola, Marc B.; Brown, Andrea M.; Hahn, Daniel V.; Thomas, Michael E.; Congdon, Elizabeth A.; Mehoke, Douglas S.

2014-09-01

220

Simulation of BaBar Drift Chamber  

SciTech Connect

The BaBar drift chamber (DCH) is used to measure the properties of charged particles created from e{sup +}e{sup -} collisions in the PEP-II asymmetric-energy storage rings by making precise measurements of position, momentum and ionization energy loss (dE/dx). In October of 2005, the PEP-II storage rings operated with a luminosity of 10 x 10{sup 33} cm{sup -2}s{sup -1}; the goal for 2007 is a luminosity of 20 x 10{sup 33} cm{sup -2}s{sup -1}, which will increase the readout dead time, causing uncertainty in drift chamber measurements to become more significant in physics results. The research described in this paper aims to reduce position and dE/dx uncertainties by improving our understanding of the BaBar drift chamber performance. A simulation program--called GARFIELD--is used to model the behavior of the drift chamber with adjustable parameters such as gas mixture, wire diameter, voltage, and magnetic field. By exploring the simulation options offered in GARFIELD, we successfully produced a simulation model of the BaBar drift chamber. We compared the time-to-distance calibration from BaBar to that calculated by GARFIELD to validate our model as well as check for discrepancies between the simulated and calibrated time-to-distance functions, and found that for a 0{sup o} entrance angle there is a very good match between calibrations, but at an entrance angle of 90{sup o} the calibration breaks down. Using this model, we also systematically varied the gas mixture to find one that would optimize chamber operation, which showed that the gas mixture of 80:20 Helium:isobutane is a good operating point, though more calculations need to be done to confirm that it is the optimal mixture.

Anderson, Rachel; /Wisconsin U., Eau Claire /SLAC

2006-09-27

221

Lightweight Chambers for Thrust Cell Applications  

NASA Technical Reports Server (NTRS)

Traditional metals like steel and copper alloys have been used for many years to fabricate injector and chamber components of thruster assemblies. While the materials perform well, reducing engine weights would help existing and future vehicles gain performance and payload capability. It may now be possible to reduce current thruster weights up to 50% by applying composite materials. In this task, these materials are being applied to an existing thrust cell design to demonstrate new fabrication processes and potential weight savings. Two ceramic matrix composite (CMC) designs, three polymer matrix composite (PMC) designs, and two metal matrix composite (MMC) designs are being fabricated as small chamber demonstration units. In addition, a new alloy of copper, chrome, and niobium (Cu-8Cr-4Nb) is being investigated for thrust chamber liners since it offers higher strength and increased cycle life over traditional alloys. This new alloy is being used for the liner in each MMC and PMC demonstration unit. During June-August of 2000, hot-fire testing of each unit is planned to validate designs in an oxygen/hydrogen environment at chamber pressures around 850 psi. Although the weight savings using CMC materials is expected to be high, they have proven to be much harder to incorporate into chamber designs based on current fabrication efforts. However, the PMC & MMC concepts using the Cu-8Cr-4Nb liner are nearly complete and ready for testing. Additional efforts intend to use the PMC & MMC materials to fabricate a full size thrust chamber (60K lb(sub f) thrust class). The fabrication of this full size unit is expected to be complete by October 2000, followed by hot-fire testing in November-December 2000.

Elam, S.; Effinger, M.; Holmes, R.; Lee, J.; Jaskowiak, M.

2000-01-01

222

A new environmental chamber for evaluation of gas-phase chemical mechanisms and secondary aerosol formation  

NASA Astrophysics Data System (ADS)

A new state-of-the-art indoor environmental chamber facility for the study of atmospheric processes leading to the formation of ozone and secondary organic aerosol (SOA) has been constructed and characterized. The chamber is designed for atmospheric chemical mechanism evaluation at low reactant concentrations under well-controlled environmental conditions. It consists of two collapsible 90 m 3 FEP Teflon film reactors on pressure-controlled moveable frameworks inside a temperature-controlled enclosure flushed with purified air. Solar radiation is simulated with either a 200 kW Argon arc lamp or multiple blacklamps. Results of initial characterization experiments, all carried out at ˜300-305 K under dry conditions, concerning NO x and formaldehyde offgasing, radical sources, particle loss rates, and background PM formation are described. Results of initial single organic-NO x and simplified ambient surrogate-NO x experiments to demonstrate the utility of the facility for mechanism evaluation under low NO x conditions are summarized and compared with the predictions of the SAPRC-99 chemical mechanism. Overall, the results of the initial characterization and evaluation indicate that this new environmental chamber can provide high quality mechanism evaluation data for experiments with NO x levels as low as ˜2 ppb, though the results indicate some problems with the gas-phase mechanism that need further study. Initial evaluation experiments for SOA formation, also carried out under dry conditions, indicate that the chamber can provide high quality secondary aerosol formation data at relatively low hydrocarbon concentrations.

Carter, William P. L.; Cocker, David R.; Fitz, Dennis R.; Malkina, Irina L.; Bumiller, Kurt; Sauer, Claudia G.; Pisano, John T.; Bufalino, Charles; Song, Chen

223

Nuclear Facilities  

NSDL National Science Digital Library

In order to produce nuclear weapons, each country must have facilities to produce and refine the nuclear materials, conduct research on weapon design, and store the completed weapons. The interactives in this collection allow you to explore the nuclear facilities of the nuclear powers (both declared and undeclared).

Griffith, Christopher

224

Measurements of a 1/4-scale model of an explosives firing chamber  

SciTech Connect

In anticipation of increasingly stringent environmental regulations, Lawrence Livermore National Laboratory (LLNL) proposes to construct a 60-kg firing chamber to provide blast-effects containment for most of its open-air, high-explosive, firing operations. Even though these operations are within current environmental limits, containment of the blast effects and hazardous debris will further drastically reduce emissions to the environment and minimize the generated hazardous waste. The major design consideration of such a chamber is its overall structural dynamic response in terms of long-term containment of all blast effects from repeated internal detonations of high explosives. Another concern is how much other portions of the facility outside the firing chamber must be hardened to ensure personnel protection in the event of an accidental detonation while the chamber door is open. To assess these concerns, a 1/4-scale replica model of the planned contained firing chamber was designed, constructed, and tested with scaled explosive charges ranging from 25 to 125% of the operational explosives limit of 60 kg. From 16 detonations of high explosives, 880 resulting strains, blast pressures, and temperatures within the model were measured to provide information for the final design. Factors of safety for dynamic yield of the firing chamber structure were calculated and compared to the design criterion of totally elastic response. The rectangular, reinforced-concrete chamber model exhibited a lightly damped vibrational response that placed the structure in alternating cycles of tension and compression. During compression, both the reinforcing steel and the concrete remained elastic.

Pastrnak, J.W.; Baker, C.F.; Simmons, L.F.

1995-01-27

225

Outdoor smog chamber experiments to test photochemical models. Final report May 78-May 81  

SciTech Connect

The smog chamber facility of the University of North Carolina was used in a study to provide experimental data for developing and testing kinetic mechanisms of photochemical smog formation. The smog chamber, located outdoors in rural North Carolina, is an A-frame structure covered with Teflon film. Because the chamber is partitioned into two sections, each with a volume of 156 cu m, two experiments can be conducted simultaneously. The dual chamber is operated under natural conditions of solar radiation, temperature, and relative humidity. In this study, 115 dual all-day experiments were conducted using NOx and a variety of organic species. The organic compounds investigated included various paraffins, olefins, aromatics and oxygenates, both singly and in mixtures of two or more components. In this report the data collected over the three-year period of the study are described. The experimental procedures and analytical methods used in this study and the limitations and uncertainties of the data are discussed. Guidance for modeling of the data is also given, including a detailed discussion of how to estimate photolytic rate constants from the available UV and total solar radiation data and how to treat such chamber artifacts as dilution, wall sources and losses of pollutants, and reactivity of the background air.

Feffries, H.E.; Kamens, R.M.; Sexron, K.G.; Gerhardt, A.A.

1982-04-01

226

Performance Of A Liquid Argon Time Projection Chamber Exposed To The WANF Neutrino Beam  

Microsoft Academic Search

We present the results of the first exposure of a Liquid Argon TPC to a multi-GeV neutrino beam. The data have been collected with a 50 liters ICARUS-like chamber located between the CHORUS and NOMAD experiments at the CERN West Area Neutrino Facility (WANF). We discuss both the instrumental performance of the detector and its capability to identify and reconstruct

P. Benetti; M. Bonesini; A Borio di Tigliole; B. Boschetti; A. Bueno; E. Calligarich; F. Casagrande; D. Cavalli; F. Cavanna; P. Cennini; Sandro Centro; E Cesana; D Cline; A Curioni; I De Mitri; C De Vecchi; R Dolfini; A Ferrari; A. Guglielmi; J Kisiel; G Mannocchi; A Martinez de la Ossa; C Matthey; F Mauri; C Montanari; S Navas; P Negri; Marino Nicoletto; S Otwinowski; M Paganoni; O Palamara; Adriano Pepato; L Periale; G Piano Mortari; P Picchi; F Pietropaolo; A Puccini; A Pullia; S Ragazzi; T Rancati; A Rappoldi; G L Raselli; N Redaelli; E Rondio; André Rubbia; Carlo Rubbia; P R Sala; F Sergiampietri; J Sobczyk; S Suzuki; T Tabarelli de Fatis; M Terrani; F Terranova; A Tonazzo; Sandro Ventura; C Vignoli; H Wang; Zalewska A

2006-01-01

227

Performance Of A Liquid Argon Time Projection Chamber Exposed To The WANF Neutrino Beam  

E-print Network

We present the results of the first exposure of a Liquid Argon TPC to a multi-GeV neutrino beam. The data have been collected with a 50 liters ICARUS-like chamber located between the CHORUS and NOMAD experiments at the CERN West Area Neutrino Facility (WANF). We discuss both the instrumental performance of the detector and its capability to identify and reconstruct low multiplicity neutrino interactions.

Arneodo, F; Bonesini, M; Borio di Tigliole, A; Boschetti, B; Bueno, A; Calligarich, E; Casagrande, F; Cavalli, D; Cavanna, F; Cennini, P; Centro, Sandro; Cesana, E; Cline, D; Curioni, A; De Mitri, I; De Vecchi, C; Dolfini, R; Ferrari, A; Ghezzi, A; Guglielmi, A; Kisiel, J; Mannocchi, G; Martinez de la Ossa, A; Matthey, C; Mauri, F; Montanari, C; Navas, S; Negri, P; Nicoletto, Marino; Otwinowski, S; Paganoni, M; Palamara, O; Pepato, Adriano; Periale, L; Piano Mortari, G; Picchi, P; Pietropaolo, F; Puccini, A; Pullia, A; Ragazzi, S; Rancati, T; Rappoldi, A; Raselli, G L; Redaelli, N; Rondio, E; Rubbia, André; Rubbia, Carlo; Sala, P R; Sergiampietri, F; Sobczyk, J; Suzuki, S; Tabarelli de Fatis, T; Terrani, M; Terranova, F; Tonazzo, A; Ventura, Sandro; Vignoli, C; Wang, H; Zalewska A

2006-01-01

228

Characteristics of a delay-line readout in a cylindrical drift chamber system  

NASA Astrophysics Data System (ADS)

This paper reports on the design, construction, and operational characteristics of a delay-line readout implemented on the cathode foils of a cylindrical drift chamber system. The readout was used to determine the position of an event along the length of the 1.74 m drift wires in the MEGA detectors used at the Los Alamos Meson Physics Facility. The performance of the system is interpreted by comparison to a PSPICE simulation, and to simple analytical models.

Barber, R.; Ahmed, M. W.; Dzemidzic, M.; Empl, A.; Hungerford, E. V.; Lan, K. J.; Wilson, J.; Cooper, M. D.; Gagliardi, C. A.; Haim, D.; Kim, G. J.; Koetke, D. D.; Tribble, R. E.; Van Ausdeln, L. A.

2002-03-01

229

Simple chamber facilitates chemiluminescent detection of bacteria  

NASA Technical Reports Server (NTRS)

Test chamber enables rapid estimation of bacteria in a test sample through the reaction of luminol and an oxidant with the cytochrome C portion of certain species of bacteria. Intensity of the light emitted in the reaction is a function of the specific bacteria in the test sample.

Marts, E. C.; Wilkins, J. R.

1970-01-01

230

Chamber of Commerce reception for Dr. Lucas  

NASA Technical Reports Server (NTRS)

Dr. William R. Lucas, Marshall's fourth Center Director (1974-1986), delivers a speech in front of a picture of the lunar landscape with Earth looming in the background while attending a Huntsville Chamber of Commerce reception honoring his achievements as Director of Marshall Space Flight Center (MSFC).

1986-01-01

231

Wave Phenomena in an Acoustic Resonant Chamber  

ERIC Educational Resources Information Center

Discusses the design and operation of a high Q acoustical resonant chamber which can be used to demonstrate wave phenomena such as three-dimensional normal modes, Q values, densities of states, changes in the speed of sound, Fourier decomposition, damped harmonic oscillations, sound-absorbing properties, and perturbation and scattering problems.…

Smith, Mary E.; And Others

1974-01-01

232

Presenting Chamber Music to Young Children  

ERIC Educational Resources Information Center

The number of professional ensembles and organizations with dedicated outreach concerts has been steadily increasing over the past decade. More recently, educational concerts pairing chamber music with young children have been documented. The work presented in this article is a study in the efficacy and feasibility of this format. Various music…

Smith, Terry Fonda

2011-01-01

233

Chamber transport for heavy ion fusion  

NASA Astrophysics Data System (ADS)

A brief review is given of research on chamber transport for HIF (heavy ion fusion) dating from the first HIF Workshop in 1976 to the present. Chamber transport modes are categorized into ballistic transport modes and channel-like modes. Four major HIF reactor studies are summarized (HIBALL-II, HYLIFE-II, Prometheus-H, OSIRIS), with emphasis on the chamber transport environment. In general, many beams are used to provide the required symmetry and to permit focusing to the required small spots. Target parameters are then discussed, with a summary of the individual heavy ion beam parameters required for HIF. The beam parameters are then classified as to their line charge density and perveance, with special emphasis on the perveance limits for radial space charge spreading, for the space charge limiting current, and for the magnetic (Alfven) limiting current. The major experiments on ballistic transport (SFFE, Sabre beamlets, GAMBLE II, NTX, NDCX) are summarized, with specific reference to the axial electron trapping limit for charge neutralization. The major experiments on channel-like transport (GAMBLE II channel, GAMBLE II self-pinch, LBNL channels, GSI channels) are discussed. The status of current research on HIF chamber transport is summarized, and the value of future NDCX-II transport experiments for the future of HIF is noted.

Olson, Craig L.

2014-01-01

234

LARGE ENVIRONMENTAL CHAMBER: AMMONIA RECOVERY CALIBRATION  

Microsoft Academic Search

The ability to accurately measure ammonia emissions from farms is an important issue both in terms of establishing emissions regulations and for effective evaluation of mitigation techniques. To address this issue, experimental trials were carried out to determine the ability to quantitatively recover ammonia released within a large environmental chamber designed to house six dairy cows or manure processing technologies.

A. M. Lefcourt

235

Replenishment of magma chambers by light inputs  

Microsoft Academic Search

Magma chambers, particularly those of basaltic composition, are often replenished by an influx of magma whose density is less than that of the resident magma. This paper describes the fundamental fluid mechanics involved in the replenishment by light inputs. If rho denotes the uniform density of the resident magma and rho-Deltarho that the input, the situation is described by the

Herbert E. Huppert; R. Stephen; J. Sparks; John A. Whitehead; Mark A. Halloworth

1986-01-01

236

Multiphysics Nuclear Thermal Rocket Thrust Chamber Analysis  

NASA Technical Reports Server (NTRS)

The objective of this effort is t o develop an efficient and accurate thermo-fluid computational methodology to predict environments for hypothetical thrust chamber design and analysis. The current task scope is to perform multidimensional, multiphysics analysis of thrust performance and heat transfer analysis for a hypothetical solid-core, nuclear thermal engine including thrust chamber and nozzle. The multiphysics aspects of the model include: real fluid dynamics, chemical reactivity, turbulent flow, and conjugate heat transfer. The model will be designed to identify thermal, fluid, and hydrogen environments in all flow paths and materials. This model would then be used to perform non- nuclear reproduction of the flow element failures demonstrated in the Rover/NERVA testing, investigate performance of specific configurations and assess potential issues and enhancements. A two-pronged approach will be employed in this effort: a detailed analysis of a multi-channel, flow-element, and global modeling of the entire thrust chamber assembly with a porosity modeling technique. It is expected that the detailed analysis of a single flow element would provide detailed fluid, thermal, and hydrogen environments for stress analysis, while the global thrust chamber assembly analysis would promote understanding of the effects of hydrogen dissociation and heat transfer on thrust performance. These modeling activities will be validated as much as possible by testing performed by other related efforts.

Wang, Ten-See

2005-01-01

237

Acoustical-Levitation Chamber for Metallurgy  

NASA Technical Reports Server (NTRS)

Sample moved to different positions for heating and quenching. Acoustical levitation chamber selectively excited in fundamental and second-harmonic longitudinal modes to hold sample at one of three stable postions: A, B, or C. Levitated object quickly moved from one of these positions to another by changing modes. Object rapidly quenched at A or C after heating in furnace region at B.

Barmatz, M. B.; Trinh, E.; Wang, T. G.; Elleman, D. D.; Jacobi, N.

1983-01-01

238

Miniature reaction chamber and devices incorporating same  

Microsoft Academic Search

The present invention generally relates to miniaturized devices for carrying out and controlling chemical reactions and analyses. In particular, the present invention provides devices which have miniature temperature controlled reaction chambers for carrying out a variety of synthetic and diagnostic applications, such as PCR amplification, nucleic acid hybridization, chemical labeling, nucleic acid fragmentation and the like.

Richard A. Mathies; Adam T. Woolley

2000-01-01

239

Presenting Chamber Music to Young Children  

Microsoft Academic Search

The number of professional ensembles and organizations with dedicated outreach concerts has been steadily increasing over the past decade. More recently, educational concerts pairing chamber music with young children have been documented. The work presented in this article is a study in the efficacy and feasibility of this format. Various music activities and ways to engage and involve the audience

Terry Fonda Smith

2011-01-01

240

Monitoring the Atmosphere in an Anaerobic Chamber  

PubMed Central

The Couloximeter, a fuel cell designed to measure trace amounts of oxygen, was used to monitor the atmosphere in an anaerobic chamber. The device, easy to operate and to maintain, allowed both major and minor fluctuations in oxygen concentration to be measured. Using a hose attached to the outlet within the box, defective (ruptured) gloves were consistently distinguishable from intact gloves. PMID:16350004

Sudo, Sara Z.; Hersch, Paul A.

1974-01-01

241

The evolutionary origin of cardiac chambers.  

PubMed

Identification of cardiac mechanisms of retinoic acid (RA) signaling, description of homologous genetic circuits in Ciona intestinalis and consolidation of views on the secondary heart field have fundamental, but still unrecognized implications for vertebrate heart evolution. Utilizing concepts from evolution, development, zoology, and circulatory physiology, we evaluate the strengths of animal models and scenarios for the origin of vertebrate hearts. Analyzing chordates, lower and higher vertebrates, we propose a paradigm picturing vertebrate hearts as advanced circulatory pumps formed by segments, chambered or not, devoted to inflow or outflow. We suggest that chambers arose not as single units, but as components of a peristaltic pump divided by patterning events, contrasting with scenarios assuming that chambers developed one at a time. Recognizing RA signaling as a potential mechanism patterning cardiac segments, we propose to use it as a tool to scrutinize the phylogenetic origins of cardiac chambers within chordates. Finally, we integrate recent ideas on cardiac development such as the ballooning and secondary/anterior heart field paradigms, showing how inflow/outflow patterning may interact with developmental mechanisms suggested by these models. PMID:15572135

Simões-Costa, Marcos S; Vasconcelos, Michelle; Sampaio, Allysson C; Cravo, Roberta M; Linhares, Vania L; Hochgreb, Tatiana; Yan, Chao Y I; Davidson, Brad; Xavier-Neto, José

2005-01-01

242

OUTDOOR SMOG CHAMBER EXPERIMENTS USING AUTOMOBILE EXHAUST  

EPA Science Inventory

Outdoor smog chamber experiments using automobile exhaust were performed in this study. The purpose of the study was to provide a data base that modelers could use to develop new, improved mechanisms for use in the Empirical Kinetics Modeling Approach (EKMA). Thirty-three dual sm...

243

IFE Chamber Development -To ETF and Beyond  

E-print Network

IFE Chamber Development - To ETF and Beyond Presentation to FESAC Development Path Panel Oct. 28), Craig Olson (SNL), Per Peterson (UCB) #12;FESAC Dev Plan 2 Outline · Multi-phase ETF · General IFE Path proceeds in 3 phases to an ETF that would be capable of putting electricity on the grid IFE Demo

244

Miniature reaction chamber and devices incorporating same  

DOEpatents

The present invention generally relates to miniaturized devices for carrying out and controlling chemical reactions and analyses. In particular, the present invention provides devices which have miniature temperature controlled reaction chambers for carrying out a variety of synthetic and diagnostic applications, such as PCR amplification, nucleic acid hybridization, chemical labeling, nucleic acid fragmentation and the like.

Mathies, Richard A. (Moraga, CA); Woolley, Adam T. (Albany, CA)

2000-10-17

245

U.S. Chamber of Commerce  

NSDL National Science Digital Library

One would be hard pressed to find a better slogan for the U.S. Chamber of Commerce than âÂÂFighting for Your BusinessâÂÂ, so it is rather fortunate that they have already effectively trademarked these exact words. With a long and storied history dating back to 1912, the U.S Chamber of Commerce is the worldâÂÂs largest not-for-profit business federation, representing over 3 million businesses and 2800 state and local chambers. Their website will be most useful to both businesspersons and those with an interest in the role this organization plays throughout the United States in terms of its effect on the creation of national and local policy regarding the climate for small and large businesses. As might be expected, the homepage contains a full-site directory, which will lead visitors to information on international trade, current issues of relevance to business, and the ChamberâÂÂs own Center for Workforce Preparation. Some visitors may also wish to sign up for their free weekly e-newsletters, which cover topics such as corporate citizenship and workforce preparation.

246

Heat-barrier coatings for combustion chambers  

NASA Technical Reports Server (NTRS)

Arc-plasma-sprayed layered coating of graded Inconel and zirconia protects film-coolant ring below injector plate of rocket engine combustion chamber. Interfacial temperature is designed for minimum buildup of stress and to avoid melting of the metal phase in the graded layers.

Carpenter, H. W.

1970-01-01

247

Chamber for Aerosol Deposition of Bioparticles  

NASA Technical Reports Server (NTRS)

Laboratory apparatus is depicted that is a chamber for aerosol deposition of bioparticles on surfaces of test coupons. It is designed for primary use in inoculating both flat and three-dimensional objects with approximately reproducible, uniform dispersions of bacterial spores of the genus Bacillus so that the objects could be used as standards for removal of the spores by quantitative surface sampling and/or cleaning processes. The apparatus is also designed for deposition of particles other than bacterial spores, including fungal spores, viruses, bacteriophages, and standard micron-sized beads. The novelty of the apparatus lies in the combination of a controllable nebulization system with a settling chamber large enough to contain a significant number of test coupons. Several companies market other nebulizer systems, but none are known to include chambers for deposition of bioparticles to mimic the natural fallout of bioparticles. The nebulization system is an expanded and improved version of commercially available aerosol generators that include nebulizers and drying columns. In comparison with a typical commercial aerosol generator, this system includes additional, higher-resolution flowmeters and an additional pressure regulator. Also, unlike a typical commercial aerosol generator, it includes stopcocks for separately controlling flows of gases to the nebulizer and drying column. To maximize the degree of uniformity of dispersion of bioaerosol, the chamber is shaped as an axisymmetrical cylinder and the aerosol generator is positioned centrally within the chamber and aimed upward like a fountain. In order to minimize electric charge associated with the aerosol particles, the drying column is made of aluminum, the drying column is in direct contact with an aluminum base plate, and three equally spaced Po-210 antistatic strips are located at the exit end of the drying column. The sides and top of the chamber are made of an acrylic polymer; to prevent accumulation of electric charge on them, they are spray-coated with an anti-static material. During use, the base plate and the sides and top of the chamber are grounded as a further measure to minimize the buildup of electric charge.

Kern, Roger; Kirschner, Larry

2008-01-01

248

A space simulation test chamber development for the investigation of radiometric properties of materials  

NASA Technical Reports Server (NTRS)

The design, fabrication, and preliminary utilization of a thermal vacuum space simulation facility are discussed. The facility was required to perform studies on the thermal radiation properties of materials. A test chamber was designed to provide high pumping speed, low pressure, a low photon level radiation background (via high emissivity, coated, finned cryopanels), internal heat sources for rapid warmup, and rotary and linear motion of the irradiated materials specimen. The radiation detection system consists of two wideband infrared photoconductive detectors, their cryogenic coolers, a cryogenic-cooled blackbody source, and a cryogenic-cooled optical radiation modulator.

Enlow, D. L.

1972-01-01

249

Development of a EUV Test Facility at the Marshall Space Flight Center  

NASA Technical Reports Server (NTRS)

This paper will describe a new EUV test facility that is being developed at the Marshall Space Flight Center (MSFC) to test EUV telescopes. Two flight programs, HiC - high resolution coronal imager (sounding rocket) and SUVI - Solar Ultraviolet Imager (GOES-R), set the requirements for this new facility. This paper will discuss those requirements, the EUV source characteristics, the wavelength resolution that is expected and the vacuum chambers (Stray Light Facility, Xray Calibration Facility and the EUV test chamber) where this facility will be used.

West, Edward; Pavelitz, Steve; Kobayashi, Ken; Robinson, Brian; Cirtain, Johnathan; Gaskin, Jessica; Winebarger, Amy

2011-01-01

250

An encoding readout method used for Multi-gap Resistive Plate Chambers (MRPCs) for muon tomography  

NASA Astrophysics Data System (ADS)

A muon tomography facility has been built in Tsinghua University. Because of the low flux of cosmic muon, an encoding readout method, based on the fine-fine configuration, was implemented for the 2880 channels induced signals from the Multi-gap Resistive Plate Chamber (MRPC) detectors. With the encoding method, the number of the readout electronics was dramatically reduced and thus the complexity and the cost of the facility was reduced, too. In this paper, the details of the encoding method, and the overall readout system setup in the muon tomography facility are described. With the commissioning of the facility, the readout method works well. The spatial resolution of all MRPC detectors are measured with cosmic muon and the preliminary imaging result are also given.

Yue, X.; Zeng, M.; Wang, Y.; Wang, X.; Zeng, Z.; Zhao, Z.; Cheng, J.

2014-09-01

251

Simulation by Monte Carlo Method of Power Varying with Time Detected by Fission Chamber in TRACY Water-Reflected System  

Microsoft Academic Search

Numerical simulation of power varying with time detected by fission chamber was performed using the continuous- energy Monte Carlo code MCNP4B to comprehend time delay of neutron detection in power burst experiments arranged for systems incorporating water reflector as well as devoid of reflector in the Transient Experiment Critical Facility (TRACY). The simulation indicated that power generation in core during

Hiroshi YANAGISAWA; Akio OHNO

2002-01-01

252

Investigation of Accuracy and Precision of Hydroxyl Radical Measurements by LIF and DOAS in the Atmosphere Simulation Chamber SAPHIR  

Microsoft Academic Search

Atmospheric OH radical measurements of known quality in terms of precision and accuracy are of paramount importance for the testing of models that are employed in atmospheric research. The accuracy of instruments used in field campaigns can best be determined in instrument intercomparisons under controlled conditions. The atmosphere simulation chamber SAPHIR in Jülich provides an excellent and unique facility for

T. Brauers; H. Dorn; H. Fuchs; A. Hofzumahaus; F. Holland; D. Poppe; L. Rupp; E. Schlosser; R. Tillmann; R. Wegener; A. Wahner

2006-01-01

253

Pressure Control System Design for a Closed Crop Growth Chamber  

NASA Technical Reports Server (NTRS)

The Controlled Ecological Life Support System (CELSS) is an area of active research at NASA. CELSS is a plant-based bioregenerative life support system for long term manned space flights where resupply is costly or impractical. The plants in a CELSS will function to convert the carbon dioxide (exhaled by the crew) into oxygen, purify non-potable water into potable quality water, and provide food for the crew. Prior to implementing a CELSS life support system, one must have knowledge on growing plants in a closed chamber under low gravity. This information will come from research to be conducted on the CELSS Test Facility that will operate on the Space Station Freedom. Currently a ground-based CELSS Test Facility is being built at NASA Ames Research Center. It is called the EDU (Engineering Development Unit). This system will allow researchers to identify issues that may cause difficulties in the development of the CELSS Test Facility and aid in the development of new needed technologies. The EDU consists of a 1 m2 crop growth chamber that is surrounded by a containment enclosure. The containment enclosure isolates the system so there is very little mass and thermal exchange with the ambient. The leakage rate is on the order of 1 % of the enclosure's volume per day (with 0.2S psi pressure difference). The thermal leakage is less than 0.5% of the electrical power supplied to the system per degree Celsius difference from the surrounding. The pressure in the containment enclosure is regulated at 62.5 Pa below the ambient by an active controller. The goal is to maintain this set point for a variety of conditions, such as a range of operating temperatures, heat load variations that occur when the lights are turned on and off, and fluctuations in ambient pressure. In addition certain transition tracking performance is required. This paper illustrates the application of some advanced systems control methods to the task of synthesizing the EDU's pressure control system.

Tsai, K.; Blackwell, C.; Harper, Lynn D. (Technical Monitor)

1994-01-01

254

School Facilities.  

ERIC Educational Resources Information Center

Describes the building designs of eight school athletic and recreational facilities, including the educational contexts and design goals. Includes information on architects and designers, construction cost, size, and occupancy date. Also provides photographs. (EV)

Athletic Business, 2002

2002-01-01

255

Health Facilities  

MedlinePLUS

Health facilities are places that provide health care. They include hospitals, clinics, outpatient care centers, and specialized care centers, such as birthing centers and psychiatric care centers. When you ...

256

Anterior chamber fixation of a posterior chamber intraocular lens: A novel technique  

PubMed Central

We aimed to evaluate the implantation of a posterior chamber intraocular lens (IOL) in the anterior chamber (AC) with the haptics passing through two iridectomies to the posterior chamber. A total of 33 eyes of 33 patients with inadequate posterior capsular support due to either previous aphakia or posterior capsular rupture during cataract extraction were included in the study. A double iridectomy was performed on all patients using a vitrectomy probe on the midperiphery of the iris. IOLs were implanted in the AC, and the haptics were passed through the iridectomies to the posterior chamber. The mean follow-up time was 25.3 months. AC hemorrhage occurred in five patients during the iridectomy procedure. Corneal edema was detected in eight of 14 patients with primary IOL insertions. Haptic dislocation was detected in only one patient. This technique may be a good alternative to scleral-fixated IOL implantation in eyes with aphakia. PMID:24817750

Kukner, A Sahap; Alagoz, Gursoy; Erdurmus, Mesut; Serin, Didem; Dogan, Umit; Y?lmaz, Turgut

2014-01-01

257

Dose rate calculations for a light ion beam fusion Laboratory Microfusion Facility  

Microsoft Academic Search

A preliminary study done on the target chamber design for a light-ion-beam-driven Laboratory Microfusion Facility (LMF) is described. The LMF will explode fusion targets with yields between 10 and 1000 MJ over a period of 30 yr inside a 1.5-m radius chamber. Activation analysis has been performed for the target chamber and the resulting dose rates calculated. The calculations were

H. Y. Khater; M. E. Sawan

1989-01-01

258

Atmospheric optical turbulence measurements in the LOTIS vacuum chamber and LOTIS collimator jitter analysis results  

NASA Astrophysics Data System (ADS)

Lockheed Martin Space Systems Company has completed the Large Optical Test and Integration Site (LOTIS) at its Sunnyvale, CA campus. Central to the LOTIS testing facility is a 6.5-meter diameter optical collimator housed in a large, temperature controlled and vibration isolated high-vacuum chamber. A measurement has been made of the atmospheric turbulence inside the LOTIS vacuum chamber testing environment at ambient pressure and temperature near floor level where distorting turbulence may be most persistent. Turbulence is one of the many components that define the overall LOTIS Collimator optical testing capabilities at ambient air pressure. Experimental measurements have been made with a non-phase-shifting Fizeau interferometer along a 50-foot horizontal propagation path in double pass. Results presented here represent root-mean-square (RMS) wavefront error over an 18-inch aperture and the corresponding atmospheric coherence length, ro (Fried's parameter). In addition, an analysis was performed to calculate the optical line-of-sight jitter response of the LOTIS Collimator system and facility due to base-level vibration disturbances. Vibration survey measurements were made using accelerometers mounted to the vacuum chamber foundation to create a Power Spectral Density (PSD) plot of the measured seismic and vacuum chamber mechanically induced vibration disturbances. The measured PSD was used as the base input to a system-level finite element model that included the LOTIS Collimator, the Flat Mirror Positioning structure and a generic Unit Under Test all mounted on the LOTIS Vibration Isolation Bench to assess the whole system jitter response. Results presented here represent the RMS jitter in nanoradians through the optical path of the LOTIS Collimator due to base-level induced seismic and chamber mechanical vibrations.

Borota, Stephen A.; Li, Laurence; Cuzner, Gregor; Hutchison, Sheldon B.; Cochrane, Andrew

2009-05-01

259

A Perfusable 3D Cell-Matrix Tissue Culture Chamber for In Situ Evaluation of Nanoparticle Vehicle Penetration and Transport  

PubMed Central

A key factor in gene or drug therapy is the development of carriers that can efficiently reach targeted cells from a distal administration. In many gene/drug delivery studies, results obtained in 2D cultures fail to translate to similar results in vivo. In this work, we developed a perfu-sable 3D chamber for studying nanoparticle penetration and transport in cell–gel soft tissue cultures. The compartmented chamber is made of a polydimethylsiloxane (PDMS) top layer with the chamber features, created using micromachined lithography, bonded to a bottom glass coverslip. A solution of cells embedded in a hydrogel is loaded in the chamber between PDMS posts that serve as anchors to the cell–matrix at the gel-media interface. The chamber offers the following unique features: (i) rapid fabrication and simplicity in assembly, (ii) direct in situ cell imaging in a plane normal to the direction of flow or action, (iii) an easily configurable and controllable environment conducive cell culture under static or interstitial flow conditions, and (iv) facile recovery of live cells from chambers for post-experimental analysis. To assess the chamber, we delivered fluorescently labeled nanoparticles of three distinct sizes to cells-embedded Matrigels in the 3D chamber under flow and static conditions. Penetration of nanoparticles were enhanced under interstitial flow while live cell imaging and flow cytometry of recovered cells revealed particle size restrictions to efficient delivery. Although designed for delivery studies, the chamber is versatile and can be easily modified. Thus it may have broad applications for biological, tissue engineering, and therapeutic studies. PMID:17969174

Ng, Chee Ping; Pun, Suzie Hwang

2009-01-01

260

Tailored vacuum chambers for ac magnets  

SciTech Connect

The proposed LAMPF-II accelerator has a 60-Hz booster synchrotron and a 3-Hz main ring. To provide a vacuum enclosure inside the magnets with low eddy-current losses and minimal field distortion, yet capable of carrying rf image currents and providing beam stabilization, we propose an innovative combination pipe. Structurally, the enclosure is high-purity alumina ceramic, which is strong, radiation resistant, and has good vacuum properties. Applied to the chamber are thin, spaced, silver conductors using adapted thick-film technology. The conductor design can be tailored to the stabilization requirements, for example, longitudinal conductors for image currents, circumferential for transverse stabilization. The inside of the chamber has a thin, resistive coating to avoid charge build-up. The overall 60-Hz power loss is less than 100 W/m.

Harvey, A.

1985-01-01

261

Development of bakelite based Resistive Plate Chambers  

E-print Network

A Comparative study has been performed on Resistive Plate Chambers made of different grades of bakelite paper laminates, produced and commercially available in India. The chambers, operated in the streamer mode using argon : tetrafluroethane : isobutane in 34:59:7 mixing ratio, are tested with cosmic rays for the efficiency and the stability with cosmic rays. A particular grade of bakelite (P-120, NEMA LI-1989 Grade XXX), used for high voltage insulation in humid conditions, was found to give satisfactory performance with stable efficiency of > 96% continuously for more than 110 days. A silicone treatment of the inner surfaces of the bakelite RPC is found to be necessary for operation of the detector.

S. Biswas; S. Bhattacharya; S. Bose; S. Chattopadhyay; S. Saha; M. K. Sharan; Y. P. Viyogi

2008-02-20

262

Gas Injection Apparatus for Vacuum Chamber  

NASA Astrophysics Data System (ADS)

We present in this article a gas injection apparatus which comprises the gas injector and its electronic command for vacuum chamber applications. Some of these applications are thin-film deposition by a pulsed laser deposition (PLD) or a cathodic arc deposition (arc-PVD) and the plasma generation. The electronic part has been developed to adjust the flow of the gas inside the vacuum chamber by controlling both of the injector's opening time and the repetition frequency to allow a better gas flow. In this case, the system works either on a pulsed mode or a continuous mode for some applications. In addition, the repetition frequency can be synchronised with a pulsed laser by an external signal coming from the laser, which is considered as an advantage for users. Good results have been obtained using the apparatus and testing with Argon and Nitrogen gases.

Almabouada, F.; Louhibi, D.; Hamici, M.

2011-12-01

263

Spar buoy construction having production and oil storage facilities and method of operation  

SciTech Connect

This patent describes a floating structure including oil storage capacity and production facilities and adapted to be anchored by catenary mooring lines at a subsea well location, the combination of: a vertical elongated hull means having means to maintain the hull means in vertical position; the hull means including a vertical oil storage chamber means for storing oil and extending for a major portion of the height of the floating structure; vertical variable ballast chamber means extending from the bottom of the storage chamber means to above the top of the oil storage chamber means and selectively filled with ballast to maintain the center of gravity of the structure a selected distance from the center of buoyancy of the structure; work chamber means in the hull means above the oil storage chamber means; means in the work chamber means and in the variable ballast chamber means for controlling the amount of ballast in the variable ballast means; means in the oil storage chamber means and in the work chamber means for feeding oil to the oil storage chamber means and for removing water therefrom as oil is introduced therein; a central longitudinal passageway through the hull means; a riser means extending into the passageway from the subsea well location and terminating at the work chamber means; means on the riser buoyant tank means and on the hull means in the central passageway for guiding relative movement between the hull means and the riser means.

Daniell, A.F.

1986-08-19

264

CFD Code Survey for Thrust Chamber Application  

NASA Technical Reports Server (NTRS)

In the quest fo find analytical reference codes, responses from a questionnaire are presented which portray the current computational fluid dynamics (CFD) program status and capability at various organizations, characterizing liquid rocket thrust chamber flow fields. Sample cases are identified to examine the ability, operational condition, and accuracy of the codes. To select the best suited programs for accelerated improvements, evaluation criteria are being proposed.

Gross, Klaus W.

1990-01-01

265

Failure investigation of gas inlet chamber  

Microsoft Academic Search

The paper presents the results of a failure investigation carried out on a cracked gas inlet chamber. The plant found a crack on a 24in. pipe, made of 304H stainless steel, near a 3\\/4in. steam purge nozzle. The plant carried out repair welding using gas tungsten arc welding. However, after the repair welding and two months service, large size intergranular

H. M. Shalaby; W. T. Riad

2008-01-01

266

Close cathode chamber: Low material budget MWPC  

NASA Astrophysics Data System (ADS)

Performance of asymmetric-type MWPC-s are presented. In this structure, referred to as Close Cathode Chamber in an earlier study, the material budget is significantly reduced on one hand by the elimination of external support frame, on the other hand by thin detector walls. In this paper it is demonstrated that the outline is compatible with large size detectors (1 m wire length), maintaining mechanical and operation stability, with total weight of 3 kg (including support structure) for a half square meter surface. The detection efficiency and response time is shown to be sufficient for L0 triggering in the ALICE VHMPID layout. Reduced sensitivity to cathode deformations (due to internal overpressure as mechanical strain) is directly demonstrated. On small sized chambers, improvement of position resolution with analog readout is evaluated, reaching 0.09 mm RMS with 2 mm wide cathode segments. Simulation results on signal time evolutions are presented. With the above studies, comparison of classical MWPC-s and the Close Cathode Chamber design is performed in all major aspects.

Varga, Dezs?; Kiss, Gábor; Hamar, Gerg?; Bencédi, Gyula

2013-01-01

267

7 CFR 58.423 - Cheese vacuumizing chamber.  

Code of Federal Regulations, 2013 CFR

...chamber. The vacuum chamber shall be satisfactorily constructed and maintained so that the product is not contaminated with rust or flaking paint. An inner liner of stainless steel or other corrosion resistant material should be...

2013-01-01

268

7 CFR 58.423 - Cheese vacuumizing chamber.  

Code of Federal Regulations, 2012 CFR

...chamber. The vacuum chamber shall be satisfactorily constructed and maintained so that the product is not contaminated with rust or flaking paint. An inner liner of stainless steel or other corrosion resistant material should be...

2012-01-01

269

7 CFR 58.423 - Cheese vacuumizing chamber.  

...chamber. The vacuum chamber shall be satisfactorily constructed and maintained so that the product is not contaminated with rust or flaking paint. An inner liner of stainless steel or other corrosion resistant material should be...

2014-01-01

270

7 CFR 58.423 - Cheese vacuumizing chamber.  

Code of Federal Regulations, 2011 CFR

...chamber. The vacuum chamber shall be satisfactorily constructed and maintained so that the product is not contaminated with rust or flaking paint. An inner liner of stainless steel or other corrosion resistant material should be...

2011-01-01

271

30 CFR 56.7807 - Flushing the combustion chamber.  

Code of Federal Regulations, 2011 CFR

...Piercing § 56.7807 Flushing the combustion chamber. The combustion chamber of a jet drill stem which has been sitting unoperated in a drill hole shall be flushed with a suitable solvent after the stem is pulled...

2011-07-01

272

30 CFR 56.7807 - Flushing the combustion chamber.  

Code of Federal Regulations, 2010 CFR

...Piercing § 56.7807 Flushing the combustion chamber. The combustion chamber of a jet drill stem which has been sitting unoperated in a drill hole shall be flushed with a suitable solvent after the stem is pulled...

2010-07-01

273

19. View northwest of Tropic Chamber reciprocal compressors (typical), in ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

19. View northwest of Tropic Chamber reciprocal compressors (typical), in machine area. - Natick Research & Development Laboratories, Climatic Chambers Building, U.S. Army Natick Research, Development & Engineering Center (NRDEC), Natick, Middlesex County, MA

274

18. View north of Tropic Chamber Worthington centrifugal compressor and ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

18. View north of Tropic Chamber Worthington centrifugal compressor and control panel, in machine area. - Natick Research & Development Laboratories, Climatic Chambers Building, U.S. Army Natick Research, Development & Engineering Center (NRDEC), Natick, Middlesex County, MA

275

23. PHOTOCOPY OF PHOTOGRAPH. View west of Tropic Chamber refrigeration ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

23. PHOTOCOPY OF PHOTOGRAPH. View west of Tropic Chamber refrigeration equipment, ca. 1955. (Source: NRDEC). - Natick Research & Development Laboratories, Climatic Chambers Building, U.S. Army Natick Research, Development & Engineering Center (NRDEC), Natick, Middlesex County, MA

276

7. Detail view west of Arctic Chamber wind tunnel shell ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

7. Detail view west of Arctic Chamber wind tunnel shell (typical) in east elevation. - Natick Research & Development Laboratories, Climatic Chambers Building, U.S. Army Natick Research, Development & Engineering Center (NRDEC), Natick, Middlesex County, MA

277

17. View northwest of Tropic Chamber refrigeration equipment, in machine ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

17. View northwest of Tropic Chamber refrigeration equipment, in machine area. - Natick Research & Development Laboratories, Climatic Chambers Building, U.S. Army Natick Research, Development & Engineering Center (NRDEC), Natick, Middlesex County, MA

278

21. PHOTOCOPY OF PHOTOGRAPH. view north of Tropic Chamber, ca. ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

21. PHOTOCOPY OF PHOTOGRAPH. view north of Tropic Chamber, ca. 1955. (Source: NRDEC). - Natick Research & Development Laboratories, Climatic Chambers Building, U.S. Army Natick Research, Development & Engineering Center (NRDEC), Natick, Middlesex County, MA

279

16. View northwest of Arctic Chamber Worthington centrifugal compressor and ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

16. View northwest of Arctic Chamber Worthington centrifugal compressor and control panel, in machine area. - Natick Research & Development Laboratories, Climatic Chambers Building, U.S. Army Natick Research, Development & Engineering Center (NRDEC), Natick, Middlesex County, MA

280

1. View southeast of Climatic Chambers Building from roof of ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. View southeast of Climatic Chambers Building from roof of Research Building. - Natick Research & Development Laboratories, Climatic Chambers Building, U.S. Army Natick Research, Development & Engineering Center (NRDEC), Natick, Middlesex County, MA

281

Dark Matter Time Projection Chamber : Recent R&D Results  

E-print Network

The Dark Matter Time Projection Chamber collaboration recently reported a dark matter limit obtained with a 10 liter time projection chamber filled with CF[subscript 4] gas. The 10 liter detector was capable of 2D tracking ...

Battat, J.B.R.

282

On-Site Wastewater Treatment Systems: Leaching Chambers  

E-print Network

Leaching chambers distribute treated wastewater into the soil. This publication lists the advantages and disadvantages of leaching chamber systems, explains how to maintain them and gives estimates of costs....

Lesikar, Bruce J.

2000-02-04

283

Utilizing Chamber Data for Developing and Validating Climate Change Models  

NASA Technical Reports Server (NTRS)

Controlled environment chambers (e.g. growth chambers, SPAR chambers, or open-top chambers) are useful for measuring plant ecosystem responses to climatic variables and CO2 that affect plant water relations. However, data from chambers was found to overestimate responses of C fluxes to CO2 enrichment. Chamber data may be confounded by numerous artifacts (e.g. sidelighting, edge effects, increased temperature and VPD, etc) and this limits what can be measured accurately. Chambers can be used to measure canopy level energy balance under controlled conditions and plant transpiration responses to CO2 concentration can be elucidated. However, these measurements cannot be used directly in model development or validation. The response of stomatal conductance to CO2 will be the same as in the field, but the measured response must be recalculated in such a manner to account for differences in aerodynamic conductance, temperature and VPD between the chamber and the field.

Monje, Oscar

2012-01-01

284

The Fluid Dynamics of Evolving Magma Chambers  

NASA Astrophysics Data System (ADS)

Recent developments in petrology indicate that fluid dynamic effects are of fundamental importance in controlling magma genesis. The forms of convection in magma chambers arise from compositional variations caused by processes such as fractional crystallization, partial melting and contamination, as well as from thermal effects. These processes, together with phase changes such as volatile exsolution, generally cause much larger density changes in magmas than the thermal effects arising from associated temperature changes. Magmas exhibit a wide range of convective phenomena not encountered in one-component fluids that are due to these compositional changes and to the differences between the diffusivities of chemical components and heat. When crystallization occurs in such multi-component systems, fluid immediately adjacent to the growing crystals is generally either depleted or enriched in heavy components and can convect away from its point of origin. Experimental studies of convection in crystallizing systems together with theoretical analyses suggest that convective separation of liquid from crystals is the dominant process of fractionation in magmas. This paper provides a synopsis of these new ideas on convection in magmas and their application to the interpretation of igneous rocks. Crystal settling is shown to be an inadequate and, in many situations, improbable mechanism for fractional crystallization. The convective motions in chambers are usually sufficiently vigorous to keep crystals in suspension, although settling can occur from thin fluid layers and within the boundary layers at the margins of a magma chamber. We propose that convective fractionation, a term introduced to embrace a wide variety of convective phenomena caused by crystallization, is the dominant mechanism for crystal fractionation. The process enables compositional and thermal gradients to be formed in magma chambers both by closed-system crystallization and by repeated replenishment in open systems. During crystallization along the margins of a chamber, highly fractionated magmas can be generated without requiring large amounts of crystallization, because the removal and concentration of chemical components affects only a small fraction of the total magma. These convective effects also give insights into many features observed in layered intrusions, including the various types of layering and the formation of different kinds of cumulate rock.

Sparks, R. S. J.; Huppert, H. E.; Turner, J. S.

1984-04-01

285

Herds of methane chambers grazing bubbles  

NASA Astrophysics Data System (ADS)

Water to air methane emissions from freshwater reservoirs can be dominated by sediment bubbling (ebullitive) events. Previous work to quantify methane bubbling from a number of Australian sub-tropical reservoirs has shown that this can contribute as much as 95% of total emissions. These bubbling events are controlled by a variety of different factors including water depth, surface and internal waves, wind seiching, atmospheric pressure changes and water levels changes. Key to quantifying the magnitude of this emission pathway is estimating both the bubbling rate as well as the areal extent of bubbling. Both bubbling rate and areal extent are seldom constant and require persistent monitoring over extended time periods before true estimates can be generated. In this paper we present a novel system for persistent monitoring of both bubbling rate and areal extent using multiple robotic surface chambers and adaptive sampling (grazing) algorithms to automate the quantification process. Individual chambers are self-propelled and guided and communicate between each other without the need for supervised control. They can maintain station at a sampling site for a desired incubation period and continuously monitor, record and report fluxes during the incubation. To exploit the methane sensor detection capabilities, the chamber can be automatically lowered to decrease the head-space and increase concentration. The grazing algorithms assign a hierarchical order to chambers within a preselected zone. Chambers then converge on the individual recording the highest 15 minute bubbling rate. Individuals maintain a specified distance apart from each other during each sampling period before all individuals are then required to move to different locations based on a sampling algorithm (systematic or adaptive) exploiting prior measurements. This system has been field tested on a large-scale subtropical reservoir, Little Nerang Dam, and over monthly timescales. Using this technique, localised bubbling zones on the water storage were found to produce over 50,000 mg m-2 d-1 and the areal extent ranged from 1.8 to 7% of the total reservoir area. The drivers behind these changes as well as lessons learnt from the system implementation are presented. This system exploits relatively cheap materials, sensing and computing and can be applied to a wide variety of aquatic and terrestrial systems.

Grinham, Alistair; Dunbabin, Matthew

2014-05-01

286

THERMAL RADIATION LOAD ON TEMPERATURE REGIMES IN PLANT GROWTH CHAMBERS  

Microsoft Academic Search

HAMASAKI T. and OKADA M. Thermal radiation load on temperature regimes in plant growth chambers. BIOTRONICS 29, 57-69, 2000. In enclosed environments such as a plant growth chamber, thermal radiation plays an important role in determining heat balance and therefore the resultant temperature regimes. In artificially illuminated chambers, a significant level of thermal radiation is emitted from the lamps and\\/or

T. HAMASAKI; M. OKADA

2000-01-01

287

Photocopy of drawing. ALTITUDE CHAMBERS ?L? & ?R? STRUCTURES. NASA, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Photocopy of drawing. ALTITUDE CHAMBERS ?L? & ?R? STRUCTURES. NASA, John F. Kennedy Space Center, Florida. Drawing 68-K-L-11213, NASA KSC, November, 1968. CHAMBER ?L? ELEVATION. Sheet 3 - Cape Canaveral Air Force Station, Launch Complex 39, Altitude Chambers, First Street, between Avenue D and Avenue E, Cape Canaveral, Brevard County, FL

288

Photocopy of drawing. ALTITUDE CHAMBERS ?L? & ?R? STRUCTURES. NASA, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Photocopy of drawing. ALTITUDE CHAMBERS ?L? & ?R? STRUCTURES. NASA, John F. Kennedy Space Center, Florida. Drawing 68-K-L-11213, NASA KSC, November, 1968. CHAMBER ?R? ELEVATION. Sheet 4 - Cape Canaveral Air Force Station, Launch Complex 39, Altitude Chambers, First Street, between Avenue D and Avenue E, Cape Canaveral, Brevard County, FL

289

On the exploration of innovative concepts for fusion chamber technology  

Microsoft Academic Search

This study, called APEX, is exploring novel concepts for fusion chamber technology that can substantially improve the attractiveness of fusion energy systems. The emphasis of the study is on fundamental understanding and advancing the underlying engineering sciences, integration of the physics and engineering requirements, and enhancing innovation for the chamber technology components surrounding the plasma. The chamber technology goals in

M. A Abdou; A Ying; N Morley; K Gulec; S Smolentsev; M Kotschenreuther; S Malang; S Zinkle; T Rognlien; P Fogarty; B Nelson; R Nygren; K McCarthy; M. Z Youssef; N Ghoniem; D Sze; C Wong; M Sawan; H Khater; R Woolley; R Mattas; R Moir; S Sharafat; J Brooks; A Hassanein; D Petti; M Tillack; M Ulrickson; T Uchimoto

2001-01-01

290

Reverberating chambers as sources of stochastic electromagnetic fields  

Microsoft Academic Search

Reverberating chambers are of recognized relevance in many EMC applications since they allow us to generate a reference electromagnetic statistical field. This paper investigates the electromagnetic field in reverberating chambers. Reverberating chambers are large overmoded cavities wherein a nonstationary electromagnetic field is present. This electromagnetic field is stochastic in nature; therefore, proper analytical tools need to be considered in order

Paolo Corona; Giuseppe Ferrara; Maurizio Migliaccio

1996-01-01

291

Neutron sensitivity of a polyethylene-walled electret ionization chamber  

Microsoft Academic Search

The electret ionization chamber is an analogue of the common ionization chamber using permanently charged electrodes - electrets. The application of such electret dosimeters for detecting X and gamma radiation primarily in personnel monitoring has been established. In the present paper the neutron sensitivity of a polyethylene-walled electret ionization chamber with parallel plate geometry was determined experimentally and theoretically for

Gunter Pretzsch

1985-01-01

292

7 CFR 58.423 - Cheese vacuumizing chamber.  

Code of Federal Regulations, 2010 CFR

... Agriculture 3 2010-01-01 2010-01-01 false Cheese vacuumizing chamber. 58.423 Section 58.423 Agriculture...and Grading Service 1 Equipment and Utensils § 58.423 Cheese vacuumizing chamber. The vacuum chamber shall be...

2010-01-01

293

Semiclosed-circuit atmosphere control in a portable recompression chamber  

NASA Technical Reports Server (NTRS)

A small portable recompression chamber is described that can be used both to treat a diver for decompression sickness or to transport him to a larger chamber complex. The device can be operated in either open circuit or semiclosed circuit atmospheres, permits two way conversation between patient and attendant, and uses an air injector for circulation of the chamber atmosphere.

Riegel, P. S.; Caudy, D. W.

1972-01-01

294

A combination drift chamber/pad chamber for very high readout rates  

SciTech Connect

Six medium-sized ({approx}1 {times} 2 m{sup 2}) drift chambers with pad and stripe readout have been constructed for and are presently operating in Fermi National Accelerator Laboratory experiment E-771. Each chamber module actually represents a pair of identical planes: two sets of anode wires, two sets of stripes, and two sets of pads. The wire planes are read out separately and represent X measurements in the coordinate system of the experiment. The twin stripe and pad planes are internally paired within the chamber modules; stripe signals represent Y measurements and pad signals combination X and Y measurements. Signals which develop on the stripes and pads are mirror (but inverted) images of what is seen on the wires. In addition to being used in the off-line pattern recognition, pad signals are also used as inputs to an on-line high transverse momentum (pt) trigger processor. While the techniques involved in the design and construction of the chambers are not novel, they may be of interest to experiments contemplating very large area, high rate chambers for future spectrometers.

Spiegel, L.; Cataldi, G.; Elia, V.; Mazur, P.; Murphy, C.T.; Smith, R.P.; Yang, W. (Fermi National Accelerator Lab., Batavia, IL (United States)); Alexopoulos, T.; Durandet, C.; Erwin, A.; Jennings, J. (Wisconsin Univ., Madison, WI (United States)); Antoniazzi, L.; Introzzi, G.; Lanza, A.; Liguori, G.; Torre, P. (Pavia Univ. (Italy) Istituto Nazionale di Fisica Nucleare, Rome (Italy)); Arenton, M.; Conetti, S.

1991-11-01

295

Instrumentation Design for HRR Measurements in a Large-Scale Fire Facility  

Microsoft Academic Search

Carleton University’s experimental atrium and tunnel facilities share a fan chamber and three large exhaust fans. Using oxygen\\u000a consumption calorimetry, the Heat Release Rates (HRR) of fires in either of these facilities can be calculated. This paper\\u000a focuses on the design of the instrumentation in the fan chamber, which was carried out using the Fire Dynamics Simulator (FDS)\\u000a and manual

Yoon J. Ko; Richard Michels; George V. Hadjisophocleous

2011-01-01

296

Proposal of a growth chamber for growing Super-Dwarf Rice in Space Agriculture  

NASA Astrophysics Data System (ADS)

Space agriculture needs to be considered to supply food for space crew who stay in space over an extended time period. So far crops such as wheat, onion, oat, pea and lettuce grew to explore the possibility of space agriculture. Although rice is a staple food for most of the world, research on rice cultivation in space has not been done much. Rice grains are nutrient-rich with carbohydrate, protein and dietary fiber. Moreover, rice is a high yield crop and harvested grains have a long shelf life. However, the plant height of standard rice cultivars is relatively long, requiring much space. In addition, rice plants require higher light intensities for greater yield. For these reasons, it is difficult to establish facilities for rice culture in a limited space with a low cost. We propose to employee a super-dwarf cultivar and a small growth chamber with a new type of LEDs. The super-dwarf rice is a short-grain japonica variety and the plant height is approximately 20 cm that is one-fifth as tall as standard cultivars. The LED light used as a light source for this study can provide full spectrum of 380 nm to 750 nm. Air temperature and humidity were controlled by a Peltier device equipped in the chamber. The characteristics of the new type of LEDs and other equipments of the chamber and the ground based performance of super-dwarf rice plants grown in the chamber will be reported.

Hirai, Hiroaki; Kitaya, Yoshiaki; Tsukamoto, Koya; Yamashita, Youichirou; Hirai, Takehiro

297

Facilities Management.  

ERIC Educational Resources Information Center

Presents responses from Matt McGovern, "School Planning and Management's" Maintenance and Operations columnist, on the issue of school facility maintenance. McGovern does not believe schools will ever likely meet acceptable levels of maintenance, nor use infrared thermography for assessing roofs, outsource all maintenance work, nor find a pressing…

Bete, Tim, Ed.

1998-01-01

298

Cryogenic Test Capability at Marshall Space Flight Center's X-ray Cryogenic Test Facility  

NASA Technical Reports Server (NTRS)

Marshall Space Flight Center's X-ray & Cryogenic Test Facility (XRCF) has been performing sub-liquid nitrogen temperature testing since 1999. Optical wavefront measurement, thermal structural deformation, mechanism functional & calibration, and simple cryo-conditioning tests have been completed. Recent modifications have been made to the facility in support of the James Webb Space Telescope (JWST) program. The chamber's payload envelope and the facility s refrigeration capacity have both been increased. Modifications have also been made to the optical instrumentation area improving access for both the installation and operation of optical instrumentation outside the vacuum chamber. The facility's capabilities, configuration, and performance data will be presented.

Kegley, Jeffrey; Baker, Mark; Carpenter, Jay; Eng, Ron; Haight, Harlan; Hogue, William; McCracken, Jeff; Siler, Richard; Wright, Ernie

2006-01-01

299

Plant growth chamber based on space proven controlled environment technology  

NASA Astrophysics Data System (ADS)

Quantum Devices, Inc., in conjunction with Percival Scientific, Inc., and the Wisconsin Center for Space Automation and Robotics (WCSAR) have developed a controlled environment plant growth chamber for terrestrial agricultural and scientific applications. This chamber incorporates controlled environment technology used in the WCSAR ASTROCULTURE™ flight unit for conducting plant research on the Space Shuttle. The new chamber, termed CERES 2010, features air humidity, temperature, and carbon dioxide control, an atmospheric contaminant removal unit, an LED lighting system, and a water and nutrient delivery system. The advanced environment control technology used in this chamber will increase the reliability and repeatability of environmental physiology data derived from plant experiments conducted in this chamber.

Ignatius, Ronald W.; Ignatius, Matt H.; Imberti, Henry J.

1997-01-01

300

Test facilities for high power electric propulsion  

NASA Technical Reports Server (NTRS)

Electric propulsion has applications for orbit raising, maneuvering of large space systems, and interplanetary missions. These missions involve propulsion power levels from tenths to tens of megawatts, depending upon the application. General facility requirements for testing high power electric propulsion at the component and thrust systems level are defined. The characteristics and pumping capabilities of many large vacuum chambers in the United States are reviewed and compared with the requirements for high power electric propulsion testing.

Sovey, James S.; Vetrone, Robert H.; Grisnik, Stanley P.; Myers, Roger M.; Parkes, James E.

1991-01-01

301

Drift chamber alignment using cosmic rays  

NASA Astrophysics Data System (ADS)

The Collider Detector at Fermilab (CDF) is a general-purpose experimental apparatus with an inner tracking detector for measuring charged particles, surrounded by a calorimeter for measurements of electromagnetic and hadronic showers and a muon detector system. We present a technique for, and results of, a precise relative alignment of the drift chamber wires of the CDF tracker. This alignment has been an important component of the track momentum calibration, which is the basis for the charged-lepton calibration for the measurement of the W boson mass at CDF.

Kotwal, Ashutosh V.; Hays, Christopher P.

2014-10-01

302

Vacuum chamber for containing particle beams  

DOEpatents

A vacuum chamber for containing a charged particle beam in a rapidly changing magnetic environment comprises a ceramic pipe with conducting strips oriented along the longitudinal axis of the pipe and with circumferential conducting bands oriented perpendicular to the longitudinal axis but joined with a single longitudinal electrical connection. When both strips and bands are on the outside of the ceramic pipe, insulated from each other, a high-resistance conductive layer, such as nickel can be coated on the inside of the pipe.

Harvey, Alexander (Los Alamos, NM)

1987-01-01

303

Sensing circuits for multiwire proportional chambers  

NASA Technical Reports Server (NTRS)

Integrated sensing circuits were designed, fabricated, and packaged for use in determining the direction and fluence of ionizing radiation passing through a multiwire proportional chamber. CMOS on sapphire was selected because of its high speed and low power capabilities. The design of the proposed circuits is described and the results of computer simulations are presented. The fabrication processes for the CMOS on sapphire sensing circuits and hybrid substrates are outlined. Several design options are described and the cost implications of each discussed. To be most effective, each chip should handle not more than 32 inputs, and should be mounted on its own hybrid substrate.

Peterson, H. T.; Worley, E. R.

1977-01-01

304

Liquid rocket engine self-cooled combustion chambers  

NASA Technical Reports Server (NTRS)

Self-cooled combustion chambers are chambers in which the chamber wall temperature is controlled by methods other than fluid flow within the chamber wall supplied from an external source. In such chambers, adiabatic wall temperature may be controlled by use of upstream fluid components such as the injector or a film-coolant ring, or by internal flow of self-contained materials; e.g. pyrolysis gas flow in charring ablators, and the flow of infiltrated liquid metals in porous matrices. Five types of self-cooled chambers are considered in this monograph. The name identifying the chamber is indicative of the method (mechanism) by which the chamber is cooled, as follows: ablative; radiation cooled; internally regenerative (Interegen); heat sink; adiabatic wall. Except for the Interegen and heat sink concepts, each chamber type is discussed separately. A separate and final section of the monograph deals with heat transfer to the chamber wall and treats Stanton number evaluation, film cooling, and film-coolant injection techniques, since these subjects are common to all chamber types. Techniques for analysis of gas film cooling and liquid film cooling are presented.

1977-01-01

305

Vacuum chamber with a supersonic-flow aerodynamic window  

DOEpatents

A supersonic flow aerodynamic window is disclosed whereby a steam ejector situated in a primary chamber at vacuum exhausts superheated steam toward an orifice to a region of higher pressure, creating a barrier to the gas in the region of higher pressure which attempts to enter through the orifice. In a mixing chamber outside and in fluid communication with the primary chamber, superheated steam and gas are combined into a mixture which then enters the primary chamber through the orifice. At the point of impact of the ejector/superheated steam and the incoming gas/superheated steam mixture, a barrier is created to the gas attempting to enter the ejector chamber. This barrier, coupled with suitable vacuum pumping means and cooling means, serves to keep the steam ejector and primary chamber at a negative pressure, even though the primary chamber has an orifice to a region of higher pressure.

Hanson, C.L.

1980-10-14

306

Vacuum chamber with a supersonic flow aerodynamic window  

DOEpatents

A supersonic flow aerodynamic window, whereby a steam ejector situated in a primary chamber at vacuum exhausts superheated steam toward an orifice to a region of higher pressure, creating a barrier to the gas in the region of higher pressure which attempts to enter through the orifice. In a mixing chamber outside and in fluid communication with the primary chamber, superheated steam and gas are combined into a mixture which then enters the primary chamber through the orifice. At the point of impact of the ejector/superheated steam and the incoming gas/superheated steam mixture, a barrier is created to the gas attempting to enter the ejector chamber. This barrier, coupled with suitable vacuum pumping means and cooling means, serves to keep the steam ejector and primary chamber at a negative pressure, even though the primary chamber has an orifice to a region of higher pressure.

Hanson, Clark L. (Livermore, CA)

1982-01-01

307

Supplemental multilayer insulation research facility  

NASA Technical Reports Server (NTRS)

The Supplemental Multilayer Insulation Research Facility (SMIRF) provides a small scale test bed for conducting cryogenic experiments in a vacuum environment. The facility vacuum system is capable of simulating a Space Shuttle launch pressure profile as well as providing a steady space vacuum environment of 1.3 x 10(exp -4) Newton/sq meter (1 x 10(exp -6) torr). Warm side boundary temperatures can be maintained constant between 111 K (200 R) and 361 K (650 R) using a temperature controlled shroud. The shroud can also simulate a typical lunar day-night temperature profile. The test hardware consists of a cryogenic calorimeter supported by the lid of the vacuum chamber. A 0.45 cu meter (120 gallon) vacuum jacketed storage/supply tank is available for conditioning the cryogen prior to use in the calorimeter. The facility was initially designed to evaluate the thermal performance of insulation systems for long-term storage in space. The facility has recently been used to evaluate the performance of various new insulation systems for LH2 and LN2 ground storage dewars.

Dempsey, P. J.; Stochl, R. J.

1995-01-01

308

Simulation of TJNAF Hall A Medium Acceptance Device Drift Chamber Operation  

NASA Astrophysics Data System (ADS)

Physicists at the Thomas Jefferson National Accelerator Facility study the scattering of high energy electrons by various targets in order to better understand the quark structure of nucleons and nuclei. The scattered particles are analyzed by spectrometers which measure the particles' momenta and trajectories. The MAD (Medium Acceptance Device) spectrometer will play an important role in many experiments planned to take place in Jefferson Lab Hall A following the 12 GeV beam energy upgrade. Its angular and momentum acceptance combined with its good track resolution capabilities will be optimal for many of these experiments. The trajectories of scattered particles are resolved by a horizontal drift chamber. Based on a simplified model of electron drift from particle tracks, we developed a program to generate and analyze a realistic data set, allowing us to determine the resolution and rate capabilities of the chamber.

Puckett, Andrew; Liyanage, Nilanga

2002-10-01

309

Extreme high-rate capable timing resistive plate chambers with ceramic electrodes  

NASA Astrophysics Data System (ADS)

The future Compressed Baryonic Matter experiment to be built at the Facility for Antiproton and Ion Research in Darmstadt, Germany, will create the highest particle densities ever created in a laboratory. One of its components, the Time-of-Flight Wall, will be comprised of Resistive Plate Chambers. The high particle fluxes expected at the most inner region, close to the beam pipe, have led to the research of new low-resistive materials to be used as electrodes. Si3N4/SiC composites are a very good candidate for this function. Their bulk resistivity, in the order of 109-1010 ? cm, allows for increased rate capabilities up to 106 s-1 cm-2. In this report, the properties of these new materials will be discussed. Also, the performance of resistive plate chambers with ceramic electrodes under irradiation in electron and proton beams will be presented.

Laso Garcia, A.; Kaspar, M.; Kämpfer, B.; Kotte, R.; Naumann, L.; Peschke, R.; Stach, D.; Wendisch, C.; Wüstenfeld, J.

2012-10-01

310

Adhesive sealing of the pulp chamber.  

PubMed

The purpose of this in vitro study was to evaluate quantitatively the ability of four different filling materials to seal the orifices of root canals as a secondary seal after root canal therapy. Forty extracted human molar teeth were used. The top of pulp chambers and distal halves of the roots were removed using an Isomet saw. The canal orifices were temporarily sealed with a gutta-percha master cone without sealer. The pulp chambers were then treated with a self-etching primer adhesive system (Clearfil SE Bond), a wet bonding system (One-Step), a 4-methacryloyloxyethyl trimellitate anhydride adhesive system (C&B Metabond), or a reinforced zinc oxide-eugenol (IRM). The specimens were randomly divided into four groups of 10 each. A fluid filtration method was used for quantitative evaluation of leakage. Measurements of fluid movement were made at 2-min intervals for 8 min. The quality of the seal of each specimen was measured by fluid filtration immediately and after 1 day, 1 wk, and 1 month. Even after 1 month the resins showed an excellent seal. Zinc oxide-eugenol had significantly more leakage when compared with the resin systems (p < 0.05). Adhesive resins should be considered as a secondary seal to prevent intraorifice microleakage. PMID:11501590

Belli, S; Zhang, Y; Pereira, P N; Pashley, D H

2001-08-01

311

Wire chamber radiation detector with discharge control  

DOEpatents

A wire chamber radiation detector (11) has spaced apart parallel electrodes (16) and grids (17, 18, 19) defining an ignition region (21) in which charged particles (12) or other ionizing radiations initiate brief localized avalanche discharges (93) and defining an adjacent memory region (22) in which sustained glow discharges (94) are initiated by the primary discharges (93). Conductors (29, 32) of the grids (18, 19) at each side of the memory section (22) extend in orthogonal directions enabling readout of the X-Y coordinates of locations at which charged particles (12) were detected by sequentially transmitting pulses to the conductors (29) of one grid (18) while detecting transmissions of the pulses to the orthogonal conductors (36) of the other grid (19) through glow discharges (94). One of the grids (19) bounding the memory region (22) is defined by an array of conductive elements (32) each of which is connected to the associated readout conductor (36) through a separate resistance (37). The wire chamber (11) avoids ambiguities and imprecisions in the readout of coordinates when large numbers of simultaneous or near simultaneous charged particles (12) have been detected. Down time between detection periods and the generation of radio frequency noise are also reduced.

Perez-Mendez, Victor (Berkeley, CA); Mulera, Terrence A. (Berkeley, CA)

1984-01-01

312

Mass spectrometer use in a large chamber  

NASA Technical Reports Server (NTRS)

The early satellites were somewhat insensitive to contamination produced during the construction and testing phases. The On-Orbit lifetime was such that contamination effects went either unnoticed or unrecognized. With today's On-Orbit lifetimes approaching 10+ years, contamination has become a paramount concern. The scientific payloads have increased in complexity and sensitivity. The ability to clean a contaminated sensor has greatly diminished. This requires better pumping systems and methods for improved monitoring. The conversion from diffusion pumped thermal vacuum chambers to cryo pumped chambers with the use of Misner traps and selective cold traps has reduced contamination. Witness samples supply a record of the condensates that remain after a testing cycle, but impart no knowledge of the contaminant migration during the cycle that may be a month in duration. Due to a customer's request that mass spectrometry be used during the testing of their spacecraft, a consultant was contracted to install a mass spectrometer to determine the feasibility of the instrument. The equipment and methodology described will start with the original system and its evolution to GE's present system.

Chuvala, Tom

1992-01-01

313

The Biological Flight Research Facility  

NASA Technical Reports Server (NTRS)

NASA Ames Research Center (ARC) is building a research facility, the Biological Flight Research Facility (BFRF), to meet the needs of life scientists to study the long-term effects of variable gravity on living systems. The facility will be housed on Space Station Freedom and is anticipated to operate for the lifetime of the station, approximately thirty years. It will allow plant and animal biologists to study the role of gravity, or its absence, at varying gravity intensities for varying periods of time and with various organisms. The principal difference between current Spacelab missions and those on Space Station Freedom, other than length of mission, will be the capability to perform on-orbit science procedures and the capability to simulate earth gravity. Initially the facility will house plants and rodents in habitats which can be maintained at microgravity or can be placed on a 2.5 meter diameter centrifuge. However, the facility is also being designed to accommodate future habitats for small primates, avian, and aquatic specimens. The centrifuge will provide 1 g for controls and will also be able to provide gravity from 0.01 to 2.0 g for threshold gravity studies as well as hypergravity studies. Included in the facility are a service unit for providing clean chambers for the specimens and a glovebox for manipulating the plant and animal specimens and for performing experimental protocols. The BFRF will provide the means to conduct basic experiments to gain an understanding of the effects of microgravity on the structure and function of plants and animals, as well as investigate the role of gravity as a potential countermeasure for the physiological changes observed in microgravity.

Johnson, Catherine C.

1993-01-01

314

High Thermal Conductivity NARloy-Z-Diamond Composite Combustion Chamber Liner For Advanced Rocket Engines  

NASA Technical Reports Server (NTRS)

Advanced high thermal conductivity materials research conducted at NASA Marshall Space Flight Center (MSFC) with state of the art combustion chamber liner material NARloy-Z showed that its thermal conductivity can be increased significantly by adding diamond particles and sintering it at high temperatures. For instance, NARloy-Z containing 40 vol. percent diamond particles, sintered at 975C to full density by using the Field assisted Sintering Technology (FAST) showed 69 percent higher thermal conductivity than baseline NARloy-Z. Furthermore, NARloy-Z-40vol. percent D is 30 percent lighter than NARloy-Z and hence the density normalized thermal conductivity is 140 percent better. These attributes will improve the performance and life of the advanced rocket engines significantly. By one estimate, increased thermal conductivity will directly translate into increased turbopump power up to 2X and increased chamber pressure for improved thrust and ISP, resulting in an expected 20 percent improvement in engine performance. Follow on research is now being conducted to demonstrate the benefits of this high thermal conductivity NARloy-Z-D composite for combustion chamber liner applications in advanced rocket engines. The work consists of a) Optimizing the chemistry and heat treatment for NARloy-Z-D composite, b) Developing design properties (thermal and mechanical) for the optimized NARloy-Z-D, c) Fabrication of net shape subscale combustion chamber liner, and d) Hot fire testing of the liner for performance. FAST is used for consolidating and sintering NARlo-Z-D. The subscale cylindrical liner with built in channels for coolant flow is also fabricated near net shape using the FAST process. The liner will be assembled into a test rig and hot fire tested in the MSFC test facility to determine performance. This paper describes the development of this novel high thermal conductivity NARloy-Z-D composite material, and the advanced net shape technology to fabricate the combustion chamber liner. Properties of optimized NARloy-Z-D composite material will also be presented.

Bhat, Biliyar N.; Ellis, David; Singh, Jogender

2014-01-01

315

Measurements of a 1/4-scale model of a 60-kg explosives firing chamber  

SciTech Connect

In anticipation of increasingly stringent environmental regulations, Lawrence Livermore National Laboratory (LLNL) proposes to construct a 60-kg firing chamber to provide blast-effects containment for, most of its open-air, high-explosive, firing operations. Even though these operations are within current environmental limits, containment of the blast effects and hazardous debris will further drastically reduce emissions to the environment and minimize the generated hazardous waste. The major design consideration of such a chamber is its overall structural dynamic response in terms of long-term containment of all blast effects from repeated internal detonations of high explosives. Another concern is how much other portions of the facility must be hardened to ensure personnel protection in the event of an accidental detonation. To assess these concerns, a 1/4-scale replica model of the planned contained firing chamber was designed, constructed, and tested with scaled explosive charges ranging from 25 to 125% of the operational explosives limit of 60 kg. From 16 detonations of high explosives, 880 resulting strains, blast pressures, and temperatures within the model were measured. Factors of safety for dynamic yield of the firing chamber structure were calculated and compared to the design criterion of totally elastic response. The rectangular, reinforced-concrete chamber model exhibited a lightly damped vibrational response that placed the structure in alternating cycles of tension and compression. During compression, both the reinforcing steel and the concrete remained elastic. During tension, the reinforcing steel remained elastic, but the concrete elastic limit was exceeded in two areas, the center spans of the ceiling and the north wall, where elastic safety factors as low as 0.66 were obtained, thus indicating that the concrete would be expected to crack in those areas. Indeed, visual post-test inspection of those areas revealed tight cracks in the concrete.

Pastrnak, J.W.; Baker, C.F.; Simmons, L.F.

1995-01-27

316

Magma chambers: Formation, local stresses, excess pressures, and compartments  

NASA Astrophysics Data System (ADS)

An existing magma chamber is normally a necessary condition for the generation of a large volcanic edifice. Most magma chambers form through repeated magma injections, commonly sills, and gradually expand and change their shapes. Highly irregular magma-chamber shapes are thermo-mechanically unstable; common long-term equilibrium shapes are comparatively smooth and approximate those of ellipsoids of revolution. Some chambers, particularly small and sill-like, may be totally molten. Most chambers, however, are only partially molten, the main part of the chamber being crystal mush, a porous material. During an eruption, magma is drawn from the crystal mush towards a molten zone beneath the lower end of the feeder dyke. Magma transport to the feeder dyke, however, depends on the chamber's internal structure; in particular on whether the chamber contains pressure compartments that are, to a degree, isolated from other compartments. It is only during large drops in the hydraulic potential beneath the feeder dyke that other compartments become likely to supply magma to the erupting compartment, thereby contributing to its excess pressure (the pressure needed to rupture a magma chamber) and the duration of the eruption. Simple analytical models suggest that during a typical eruption, the excess-pressure in the chamber decreases exponentially. This result applies to a magma chamber that (a) is homogeneous and totally fluid (contains no compartments), (b) is not subject to significant replenishment (inflow of new magma into the chamber) during the eruption, and (c) contains magma where exsolution of gas has no significant effect on the excess pressure. For a chamber consisting of pressure compartments, the exponential excess-pressure decline applies primarily to a single erupting compartment. When more than one compartment contributes magma to the eruption, the excess pressure may decline much more slowly and irregularly. Excess pressure is normally similar to the in-situ tensile strength of the host rock, 0.5-9 MPa. These in-situ strength estimates are based on hydraulic fracture measurements in drill-holes worldwide down to crustal depths of about 9 km. These measurements do not support some recent magma-chamber stress models that predict (a) extra gravity-related wall-parallel stresses at the boundaries of magma chambers and (b) magma-chamber excess pressures prior to rupture of as much as hundreds of mega-pascals, particularly at great depths. General stress models of magma chambers are of two main types: analytical and numerical. Earlier analytical models were based on a nucleus-of-strain source (a 'point pressure source') for the magma chamber, and have been very useful for rough estimates of magma-chamber depths from surface deformation during unrest periods. More recent models assume the magma chamber to be axisymmetric ellipsoids or, in two-dimensions, ellipses of various shapes. Nearly all these models use the excess pressure in the chamber as the only loading (since lithostatic stress effects are then automatically taken into account), assume the chamber to be totally molten, and predict similar local stress fields. The predicted stress fields are generally in agreement with the world-wide stress measurements in drill-holes and, in particular, with the in-situ tensile-strength estimates. Recent numerical models consider magma-chambers of various (ideal) shapes and sizes in relation to their depths below the Earth's surface. They also take into account crustal heterogeneities and anisotropies; in particular the effects of the effects of a nearby free surface and horizontal and inclined (dipping) mechanical layering. The results show that the free surface may have strong effects on the local stresses if the chamber is comparatively close to the surface. The mechanical layering, however, may have even stronger effects. For realistic layering, and other heterogeneities, the numerical models predict complex local stresses around magma chambers, with implications for dyke paths, dyke arrest, and ring-fault formation.

Gudmundsson, Agust

2012-09-01

317

SEM Facility for Examination of Reactive and Radioactive Materials  

Microsoft Academic Search

A scanning electron microscope (SEM) facility for the examination of tritium-containing materials is operational at Mound Laboratory. The SEM is installed with the sample chamber incorporated as an integral part of an inert gas glovebox facility to enable easy handling of radioactive and pyrophoric materials. A standard SEM (ETEC Model B-1) was modified to meet dimensional, operational, and safety-related requirements.

G. L. Downs; P. A. Tucker

1973-01-01

318

Design and characterization of a smog chamber for studying gas-phase chemical mechanisms and aerosol chemistry  

NASA Astrophysics Data System (ADS)

We describe here characterization of a new state-of-the-art smog chamber facility for studying atmospheric gas phase and aerosol chemistry. The chamber consists of a 30 m3 fluorinated ethylene propylene (FEP) Teflon film reactor suspended in a temperature-controlled enclosure equipped with two banks of black lamps as the light source. Temperature can be set in the range from -10 °C to 40 °C at accuracy of ±1 °C as measured by eight temperature sensors inside the enclosure and one just inside the reactor. Matrix air can be purified with NMHCs < 0.5 ppb, NOx/O3/carbonyls < 1 ppb and particles < 1 cmchamber are determined and included in the Master Chemical Mechanism to evaluate and model propene-NOx-air irradiation experiments. The results indicate that this new smog chamber can provide high quality data for mechanism evaluation. Results of ?-pinene dark ozonolysis experiments revealed SOA yields comparable to those from other chamber studies, and the two-product model gives a good fit for the yield data obtained in this work. Characterization experiments demonstrate that our GIG-CAS smog chamber facility can be used to provide valuable data for gas-phase mechanisms and aerosol chemistry.

Wang, X.; Liu, T.; Bernard, F.; Ding, X.; Wen, S.; Zhang, Y.; Zhang, Z.; He, Q.; Lü, S.; Chen, J.; Saunders, S.; Yu, J.

2013-08-01

319

Design and characterization of a smog chamber for studying gas-phase chemical mechanisms and aerosol formation  

NASA Astrophysics Data System (ADS)

We describe here characterization of a new state-of-the-art smog chamber facility for studying atmospheric gas-phase and aerosol chemistry. The chamber consists of a 30 m3 fluorinated ethylene propylene (FEP) Teflon film reactor housed in a temperature-controlled enclosure equipped with black lamps as the light source. Temperature can be set in the range from -10 to 40 °C at accuracy of ±1 °C as measured by eight temperature sensors inside the enclosure and one just inside the reactor. Matrix air can be purified with non-methane hydrocarbons (NMHCs) < 0.5 ppb, NOx/O3/carbonyls < 1 ppb and particles < 1 cm-3. The photolysis rate of NO2 is adjustable between 0 and 0.49 min-1. At 298 K under dry conditions, the average wall loss rates of NO, NO2 and O3 were measured to be 1.41 × 10-4 min-1, 1.39 × 10-4 min-1 and 1.31 × 10-4 min-1, respectively, and the particle number wall loss rate was measured to be 0.17 h-1. Auxiliary mechanisms of this chamber are determined and included in the Master Chemical Mechanism to evaluate and model propene-NOx-air irradiation experiments. The results indicate that this new smog chamber can provide high-quality data for mechanism evaluation. Results of ?-pinene dark ozonolysis experiments revealed secondary organic aerosol (SOA) yields comparable to those from other chamber studies, and the two-product model gives a good fit for the yield data obtained in this work. Characterization experiments demonstrate that our Guangzhou Institute of Geochemistry, Chinese Academy Sciences (GIG-CAS), smog chamber facility can be used to provide valuable data for gas-phase chemistry and secondary aerosol formation.

Wang, X.; Liu, T.; Bernard, F.; Ding, X.; Wen, S.; Zhang, Y.; Zhang, Z.; He, Q.; Lü, S.; Chen, J.; Saunders, S.; Yu, J.

2014-01-01

320

Nuclear Fission Investigation with Twin Ionization Chamber  

SciTech Connect

The purpose of the present paper was to report the recent results, obtained in development of digital pulse processing mathematics for prompt fission neutron (PFN) investigation using twin ionization chamber (TIC) along with fast neutron time-of-flight detector (ND). Due to well known ambiguities in literature (see refs. [4, 6, 9 and 11]), concerning a pulse induction on TIC electrodes by FF ionization, we first presented detailed mathematical analysis of fission fragment (FF) signal formation on TIC anode. The analysis was done using Ramo-Shockley theorem, which gives relation between charged particle motion between TIC electrodes and so called weighting potential. Weighting potential was calculated by direct numerical solution of Laplace equation (neglecting space charge) for the TIC geometry and ionization, caused by FF. Formulae for grid inefficiency (GI) correction and digital pulse processing algorithms for PFN time-of-flight measurements and pulse shape analysis are presented and discussed.

Zeynalova, O.; Zeynalov, Sh. [JINR-Joint Institute for Nuclear Research, Dubna, Moscow region (Russian Federation); Nazarenko, M. [Moscow State Institute of Radioengineering and Automation, 78 Vernadski Avenue, 119454 Moscow (Russian Federation); Hambsch, F.-J.; Oberstedt, S. [EC-JRC Institute for Reference Materials and Measurements, Retieseweg 111, 2440 Geel (Belgium)

2011-11-29

321

Advances in high chamber pressure propulsion  

NASA Technical Reports Server (NTRS)

NASA has been involved in the development of improved high thrust booster rocket engines to meet the propulsion requirements of launch vehicles such as the Space Shuttle. Solutions that NASA/Marshall Space Flight Center pursued to accomplish the high performance, long life goals set for SSME are discussed. In addition, currently projected requirements for liquid rocket engines have identified liquid oxygen/hydrocarbon-fueled engines for booster application in the near future. These advanced hydrocarbon-fueled engines will require improvements in performance and life to be suitable for their projected missions. Raising chamber pressure to increase performance and reduce engine envelope are the key objectives in hydrocarbon-fueled engine technology. This paper traces the history of advances in high pressure rocket engine systems and the challenges it presents.

Mccool, A. A.; Richmond, R. J.

1986-01-01

322

Fabrication of GRCop-84 Rocket Thrust Chambers  

NASA Technical Reports Server (NTRS)

GRCop-84, a copper alloy, Cu-8 at% Cr-4 at% Nb developed at NASA Glenn Research Center for regeneratively cooled rocket engine liners has excellent combinations of elevated temperature strength, creep resistance, thermal conductivity and low cycle fatigue. GRCop-84 is produced from prealloyed atomized powder and has been fabricated into plate, sheet and tube forms as well as near net shapes. Fabrication processes to produce demonstration rocket combustion chambers will be presented and includes powder production, extruding, rolling, forming, friction stir welding, and metal spinning. GRCop-84 has excellent workability and can be readily fabricated into complex components using conventional powder and wrought metallurgy processes. Rolling was examined in detail for process sensitivity at various levels of total reduction, rolling speed and rolling temperature representing extremes of commercial processing conditions. Results indicate that process conditions can range over reasonable levels without any negative impact to properties.

Loewenthal, William S.; Ellis, David L.

2005-01-01

323

Fabrication of GRCop-84 Rocket Thrust Chambers  

NASA Technical Reports Server (NTRS)

GRCop-84, a copper alloy, Cu-8 at% Cr-4 at% Nb developed at NASA Glenn Research Center for regenerative1y cooled rocket engine liners has excellent combinations of elevated temperature strength, creep resistance, thermal conductivity and low cycle fatigue. GRCop-84 is produced from pre-alloyed atomized powder and has been fabricated into plate, sheet and tube forms as well as near net shapes. Fabrication processes to produce demonstration rocket combustion chambers will be presented and includes powder production, extruding, rolling, forming, friction stir welding, and metal spinning. GRCop-84 has excellent workability and can be readily fabricated into complex components using conventional powder and wrought metallurgy processes. Rolling was examined in detail for process sensitivity at various levels of total reduction, rolling speed and rolling temperature representing extremes of commercial processing conditions. Results indicate that process conditions can range over reasonable levels without any negative impact to properties.

Loewenthal, William; Ellis, David

2006-01-01

324

Pseudoexfoliation material on posterior chamber intraocular lenses  

PubMed Central

The presence of pseudoexfoliation material on the surface of an intraocular lens (IOL) is a rare finding. We report a series of seven cases with different patterns of pseudoexfoliation material deposition on the posterior chamber IOLs, recognized 2–20 years after cataract surgery. Six patients had an IOL implanted in the capsular bag and one in the ciliary sulcus. Two patients had undergone posterior capsulotomy. Although the pathophysiological mechanisms and clinical significance of this finding remain unknown, the careful follow-up of pseudophakic patients with known or suspected pseudoexfoliation syndrome is essential to monitor the development or progression of glaucoma, since deposition of pseudoexfoliation material continues even after cataract surgery. PMID:25143707

da Rocha-Bastos, Ricardo António; Silva, Sérgio Estrela; Prézia, Flávio; Falcão-Reis, Fernando; Melo, António B

2014-01-01

325

Performance of the TOPAZ time projection chamber  

SciTech Connect

The TOPAZ detector has began taking data at the TRISTAN e/sup +/e/sup -/ colliding beam ring in May 1987. The major detector elements including the time projection chamber (TPC) have been working quite satisfactorily. The authors report here the performance of TPC based on real e/sup +/e/sup -/ events and cosmic ray events. They measure spatial resolution of sigma/sub xy/ = 185..mu..m and sigma/sub z/ = 335..mu..m, momentum resolution of sigma/sub PT//P/sub T/ = ..sqrt..(1.5P/sub T/)/sup 2/ + (1.6)/sup 2%/ and dE/dx resolution of 4.6%.

Shirahashi, A.; Aihara, H.; Itoh, R.; Kamae, T.; Kusuki, N.; Tanaka, M.; Fujii, H.; Fujii, K.; Ikeda, H.; Iwasaki, H.

1988-02-01

326

Objective autorefraction in posterior chamber pseudophakia.  

PubMed Central

Automated refraction with the Canon RK-1 Autoref keratometer was evaluated in 110 eyes (110 patients) six to eight weeks after they had undergone extracapsular cataract extraction with posterior chamber intraocular lens implantation and achieved a best corrected visual acuity of at least 6/12. Autorefraction readings were obtained in 100 (91%) of these eyes. The agreement between autorefraction and clinical refraction data was 98% for spherical equivalence less than 0.51 dioptres (D), 95% for sphere power less than 0.51D, 94% for cylinder power less than 0.51D, and 85% for cylinder axis less than 11 degrees. Autorefraction can provide acceptably accurate postoperative refraction values in pseudophakic eyes. Images PMID:2275935

Raj, P S; Akingbehin, T; Levy, A M

1990-01-01

327

Measurement and Compensation of BPM Chamber Motion in HLS  

NASA Astrophysics Data System (ADS)

Significant horizontal drifts in the beam orbit in the storage ring of HLS (Hefei Light Source) have been seen for many years. What leads to the motion of Beam Position Monitor (BPM) chamber is thermal expansion mainly caused by the synchrotron light. To monitor the BPM chamber motions for all BPMs, a BPM chamber motion measurement system is built in real-time. The raster gauges are used to measure the displacements. The results distinctly show the relation between the BPM chamber motion and the beam current. To suppress the effect of BPM chamber motion, a compensation strategy is implemented at HLS. The horizontal drifts of beam orbit have been really suppressed within 20?m without the compensation of BPM chamber motion in the runtime.

Li, J. W.; Sun, B. G.; Cao, Y.; Xu, H. L.; Lu, P.; Li, C.; Xuan, K.; Wang, J. G.

2010-06-01

328

Climate chamber for environmentally controlled laboratory airflow experiments.  

PubMed

Climate chambers have been widely used in in vitro and in vivo studies which require controlled environmental temperature and humidity conditions. This article describes a new desktop climate chamber that was developed for application of respiratory airflows on cultured nasal epithelial cells (NEC) under controlled temperature and humidity conditions. Flow experiments were performed by connecting the climate chamber to an airflow generator via a flow chamber with cultured NEC. Experiments at two controlled climate conditions, 25 degrees C and 40% relative humidity (RH) and 37 degrees C and 80%RH, were conducted to study mucin secretion from the cultures inresponse to the flow. The new climate chamber is a relatively simple and inexpensive apparatus which can easily be connected to any flow system for climate controlled flow experiments. This chamber can be easily adjusted to various in vitro experiments, as well as to clinical studies with animals or human subjects which require controlled climate conditions. PMID:20639592

Even-Tzur, Nurit; Zaretsky, Uri; Grinberg, Orly; Davidovich, Tomer; Kloog, Yoel; Wolf, Michael; Elad, David

2010-01-01

329

Outgassing Rate Measurement of SUS430 Vacuum Chamber  

NASA Astrophysics Data System (ADS)

For reliable and stable operation of a particle accelerator, it is necessary to shield the accelerated particles inside the vacuum chambers from unwanted external stray magnetic fields. Instead of an external shield, it can be quite efficient to design a vacuum chamber itself as a magnetic shield. Therefore, we have developed a vacuum chamber with magnetic shielding properties by using the magnetic material SUS430. For this chamber not only magnetic shielding is required, but also a low outgassing rate, so that it can be used for a high intensity particle accelerator. First, we measured the outgassing rate of SUS430 using small samples with the differential pressure flow method. The results suggested that SUS430 is compatible with our low outgassing rate requirement. Then a vacuum chamber designed for installation into the synchrotron was manufactured using SUS430, and it was confirmed that the outgassing rate of the chamber is low enough.

Kato, Shinichi; Kamiya, Junichiro; Yamamoto, Kazami; Yoshimoto, Masahiro; Kinsho, Michikazu

330

Main Chamber and Preburner Injector Technology  

NASA Technical Reports Server (NTRS)

This document reports the experimental and analytical research carried out at the Penn State Propulsion Engineering Research Center in support of NASA's plan to develop advanced technologies for future single stage to orbit (SSTO) propulsion systems. The focus of the work is on understanding specific technical issues related to bi-propellant and tri-propellant thrusters. The experiments concentrate on both cold flow demonstrations and hot-fire uni-element tests to demonstrate concepts that can be incorporated into hardware design and development. The analysis is CFD-based and is intended to support the design and interpretation of the experiments and to extrapolate findings to full-scale designs. The research is divided into five main categories that impact various SSTO development scenarios. The first category focuses on RP-1/gaseous hydrogen (GH2)/gaseous oxygen (GO2) tri-propellant combustion with specific emphasis on understanding the benefits of hydrogen addition to RP-1/oxygen combustion and in developing innovative injector technology. The second category investigates liquid oxygen (LOX)/GH2 combustion at main chamber near stoichiometric conditions to improve understanding of existing LOX/GH2 rocket systems. The third and fourth categories investigate the technical issues related with oxidizer-rich and fuel-rich propulsive concepts, issues that are necessary for developing the full-flow engine cycle. Here, injector technology issues for both LOX/GH2 and LOX/RP-1 propellants are examined. The last category, also related to the full-flow engine cycle, examines injector technology needs for GO2/GH2 propellant combustion at near-stoichiometric conditions for main chamber application.

Santoro, Robert J.; Merkle, Charles L.

1999-01-01

331

A new multi-strip ionization chamber used as online beam monitor for heavy ion therapy  

NASA Astrophysics Data System (ADS)

A multi-strip ionization chamber has been built for precise and fast monitoring of the carbon beam spatial distribution at Heavy Ion Researched Facility of Lanzhou Cooling Storing Ring (HIRFL-CSR). All the detector's anode, cathode and sealed windows are made by 2 ?m aluminized Mylar film in order to minimize the beam lateral deflection. The sensitive area of the detector is (100×100) mm2, with the anode segmented in 100 strips, and specialized front-end electronics has been developed for simplifying the data acquisition and quick feedback of the relevant parameters to beam control system. It can complete one single beam profile in 200 ?s.

Xu, Zhiguo; Mao, Ruishi; Duan, Limin; She, Qianshun; Hu, Zhengguo; Li, He; Lu, Ziwei; Zhao, Qiecheng; Yang, Herun; Su, Hong; Lu, Chengui; Hu, Rongjiang; Zhang, Junwei

2013-11-01

332

Double anterior chamber in a patient with glaucoma and microspherophakia.  

PubMed

We report the case of a 16-year-old woman with microspherophakia and secondary open angle glaucoma. The patient presented with a membrane dividing the anterior chamber into two segments without edema or Descemet's membrane detachment. Slit lamp biomicroscopy, Pentacam, and specular microscopy images were obtained. Double anterior chamber is primarily found in patients with anterior chamber anomalies when there is no history of surgery or trauma. PMID:21666323

Khakshoor, Hamid; Ansari-Astaneh, Mohammad-Reza; Shoeib, Mousa; Schliesser, Joshua A; Moshirfar, Majid

2011-01-01

333

Double anterior chamber in a patient with glaucoma and microspherophakia  

PubMed Central

We report the case of a 16-year-old woman with microspherophakia and secondary open angle glaucoma. The patient presented with a membrane dividing the anterior chamber into two segments without edema or Descemet's membrane detachment. Slit lamp biomicroscopy, Pentacam, and specular microscopy images were obtained. Double anterior chamber is primarily found in patients with anterior chamber anomalies when there is no history of surgery or trauma. PMID:21666323

Khakshoor, Hamid; Ansari-Astaneh, Mohammad-Reza; Shoeib, Mousa; Schliesser, Joshua A; Moshirfar, Majid

2011-01-01

334

Transient response characteristics of test chamber Mach number  

NASA Technical Reports Server (NTRS)

The transient dynamic characteristics of a test chamber Mach number was established for a disturbance initiated in the test chamber. An approximate linear expression was given, showing that the change in the Mach number is linearly proportional to the algebraic sum of the static pressure change in the test chamber and the stagnation pressure change. The static pressure change is the dominating factor. The two pressure changes were also calculated for small Mach number variations, and these results were applied to instrumentation requirements.

Tcheng, P.

1976-01-01

335

CIF (Consolidated Incineration Facility) offgas components test facility  

SciTech Connect

The Consolidated Incineration Facility (CIF) is planned for start-up at the Savannah River Site in 1993. The CIF has a unique offgas system design utilizing state-of-the-art technology and experience gained from other radioactive/hazardous waste incinerators. A high efficiency steam-atomized offgas scrubber with separate quench and scrubber liquid recirculation loops will be used. The Offgas Components Test Facility (OCTF), a 1:10 scale CIF offgas system, will evaluate operating performance of the proposed CIF system design. The primary objectives for the OCTF include demonstration of system operability, equipment performance evaluation, and CIF start-up support. The OCTF will also demonstrate to the public our commitment to operate the CIF in a manner that meets all environmental emission requirements. The CIF will treat solid and liquid RCRA hazardous and mixed wastes, and reduce the volume of low-level beta-gamma contaminated wastes. This facility can process 560,000 ft{sup 3}/yr of variability in physical and chemical characteristics of the waste feed, a rotary kiln with a secondary combustion chamber and wet offgas scrubbing system was selected. This design will insure maximum processing versatility. 1 fig.

Burns, D.B.

1990-11-01

336

Dalhousie University Facilities Management  

E-print Network

Dalhousie University Facilities Management Interior Signage Guidelines 2012 #12;Facilities Management Interior Signage Standard Providing Excellence in Facilities Management 2 TABLE OF CONTENTS: Construction SECTION 6: Installation APPENDICES #12;Facilities Management Interior Signage Standard Providing

Brownstone, Rob

337

Confinement of ignition and yield on the National Ignition Facility  

SciTech Connect

The National Ignition Facility Target Areas and Experimental Systems has reached mid-Title I design. Performance requirements for the Target Area are reviewed and design changes since the Conceptual Design Report are discussed. Development activities confirm a 5-m radius chamber and the viability of a boron carbide first wall. A scheme for cryogenic target integration with the NIF Target Area is presented.

Tobin, M.; Karpenko, V.; Foley, D.; Anderson, A.; Burnham, A.; Reitz, T.; Latkowski, J.; Bernat, T.

1996-06-14

338

CU-LASP Test Facilities ! and Instrument Calibration Capabilities"  

E-print Network

CU-LASP Test Facilities ! and Instrument Calibration Capabilities" Ginger Drake Calibration Group of LASP's vacuum chambers · Ideal for performing top-level instrument tests ­ Thermal Vacuum tests ­ In-band light testing (EUV-IR) · Independently temperature- controlled shroud and platen · Optional 4-axis

Mojzsis, Stephen J.

339

The Radiological Accident at the Irradiation Facility in Nesvizh  

Microsoft Academic Search

On 26 October 1991 at an industrial sterilisation facility in Nesvizh, Belarus, an operator entered the irradiation chamber and was exposed to a lethal dose of radiation. This publication, the third to be issued by IAEA on irradiator accidents, describes the events leading up to the accident, the dose received by the operator, the subsequent medical management and the lessons

Richard Paynter

1998-01-01

340

LEGISLATION FOR GMO's IN NORTH AMERICA: DESIGN OF CONTAINMENT FACILITIES  

Microsoft Academic Search

I stand before you with the utmost humility. It is truly an honor to have been invited to participate in a conference that brings together the world's experts in controlled environments for biological research. As a greenhouse and growth chamber manager of University facilities for most of my professional life, I've benefited from your discoveries and applications. My talk today

Dann Adair

341

An Experimental Study of Upward Burning Over Long Solid Fuels: Facility Development and Comparison  

NASA Technical Reports Server (NTRS)

As NASA's mission evolves, new spacecraft and habitat environments necessitate expanded study of materials flammability. Most of the upward burning tests to date, including the NASA standard material screening method NASA-STD-6001, have been conducted in small chambers where the flame often terminates before a steady state flame is established. In real environments, the same limitations may not be present. The use of long fuel samples would allow the flames to proceed in an unhindered manner. In order to explore sample size and chamber size effects, two large chambers were developed at NASA GRC under the Flame Prevention, Detection and Suppression (FPDS) project. The first was an existing vacuum facility, VF-13, located at NASA John Glenn Research Center. This 6350 liter chamber could accommodate fuels sample lengths up to 2 m. However, operational costs and restricted accessibility limited the test program, so a second laboratory scale facility was developed in parallel. By stacking additional two chambers on top of an existing combustion chamber facility, this 81 liter Stacked-chamber facility could accommodate a 1.5 m sample length. The larger volume, more ideal environment of VF-13 was used to obtain baseline data for comparison with the stacked chamber facility. In this way, the stacked chamber facility was intended for long term testing, with VF-13 as the proving ground. Four different solid fuels (adding machine paper, poster paper, PMMA plates, and Nomex fabric) were tested with fuel sample lengths up to 2 m. For thin samples (papers) with widths up to 5 cm, the flame reached a steady state length, which demonstrates that flame length may be stabilized even when the edge effects are reduced. For the thick PMMA plates, flames reached lengths up to 70 cm but were highly energetic and restricted by oxygen depletion. Tests with the Nomex fabric confirmed that the cyclic flame phenomena, observed in small facility tests, continued over longer sample. New features were also observed at the higher oxygen/pressure conditions available in the large chamber. Comparison of flame behavior between the two facilities under identical conditions revealed disparities, both qualitative and quantitative. This suggests that, in certain ranges of controlling parameters, chamber size and shape could be one of the parameters that affect the material flammability. If this proves to be true, it may limit the applicability of existing flammability data.

Kleinhenz, Julie; Yuan, Zeng-Guang

2011-01-01

342

Dielectric liquid ionization chambers for detecting fast neutrons  

E-print Network

Three ionization chambers with different geometries have been constructed and filled with dielectric liquids for detection of fast neutrons. The three dielectric liquids studied were Tetramethylsilane (TMS), Tetramethylpentane ...

Boyd, Erin M

2008-01-01

343

The major parameters affecting temperature inside inhalation chambers.  

PubMed

Variations in inhalation chamber temperature can produce alterations in animal physiology, metabolism of foreign compounds as well as the chemical interaction of pollutant aerosols. This report presents the results of an investigation of the different mechanisms of heat transfer in a 380 L inhalation chamber and discusses the relative effectiveness of various methods that may be used to maintain a uniform chamber temperature during animal exposures. The thermal characteristics of the inhalation chamber were studied using an array of 40 thermocouples, with and without rats in the chamber and with and without 5 cm fiber glass insulation surrounding the chamber. Temperature profiles were measured with different animal loadings and intake air temperatures. An effective heat transfer coefficient of 6.6 +/- 1.8 W/m2 degrees C was determined for the stainless steel walls of the chamber. Heat balance studies with rats in this chamber have shown that with room air intake at a flow rate of 100 L/min, the stainless steel chamber walls were effective at removing approximately ninety percent of the animal heat as compared to the airstream. PMID:7395755

Bernstein, D M; Drew, R T

1980-06-01

344

Cooling of rocket thrust chambers with liquid oxygen  

NASA Technical Reports Server (NTRS)

Rocket engines using high pressure liquid oxygen (LOX) and kerosene (RP-1) as the propellants have been considered for future launch vehicle propulsion. Generally, in regeneratively cooled engines, the fuel is used to cool the combustion chamber. However, hydrocarbons such as RP-1 are limited in their cooling capability at high temperatures and pressures. Therefore, LOX is being considered as an alternative coolant. However, there has been concern as to the effect on the integrity of the chamber liner if oxygen leaks into the combustion zone through fatigue cracks that may develop between the cooling passages and the hot-gas side wall. To address this concern, an investigation was previously conducted with simulated fatigue cracks upstream of the thrust chamber throat. When these chambers were tested, an unexpected melting in the throat region developed which was not in line with the simulated fatigue cracks. The current experimental program was conducted in order to determine the cause for the failure in the earlier thrust chambers and to further investigate the effects of cracks in the thrust chamber liner upstream of the throat. The thrust chambers were tested at oxygen-to-fuel mixture ratios from 1.5 to 2.86 at a nominal chamber pressure of 8.6 MPa. As a result of the test series, the reason for the failure occurring in the earlier work was determined to be injector anomalies. The LOX leaking through the simulated fatigue cracks did not affect the integrity of the chambers.

Armstrong, Elizabeth S.; Schlumberger, Julie A.

1990-01-01

345

Test chamber for low-background IR focal plane testing  

NASA Technical Reports Server (NTRS)

A unique and versatile vacuum chamber has been designed for JPL's IR Focal Plane Technology Group. This chamber is equipped with multiple ports for cryogen and electrical vacuum feedthroughs, pumping units, vacuum gages, sources, and detector camera heads. The design incorporates a liquid-nitrogen-cooled optical table and radiation shield for low-background IR detector testing. Focal planes can be tested at temperatures ranging from 300 K to that of liquid helium. This paper describes the design and construction of this low-background IR focal plane test chamber and discusses some of its distinctive features. An analysis of the test chamber's performance is also presented.

Staller, Craig; Capps, Richard W.; Butler, Douglas; Moss, Nancy; Norwood, Wynn

1989-01-01

346

Hot fire fatigue testing results for the compliant combustion chamber  

NASA Technical Reports Server (NTRS)

A hydrogen-oxygen subscale rocket combustion chamber was designed incorporating an advanced design concept to reduce strain and increase life. The design permits unrestrained thermal expansion of a circumferential direction and, thereby, provides structural compliance during the thermal cycling of hot-fire testing. The chamber was built and test fired at a chamber pressure of 4137 kN/sq m (600 psia) and a hydrogen-oxygen mixture ratio of 6.0. Compared with a conventional milled-channel configuration, the new structurally compliant chamber had a 134 or 287 percent increase in fatigue life, depending on the life predicted for the conventional configuration.

Pavli, Albert J.; Kazaroff, John M.; Jankovsky, Robert S.

1992-01-01

347

Explosive Containment Chamber Vulnerability to Chemical Munition Fragment Impact  

SciTech Connect

Scenarios in which the explosive burster charge in a chemical munition accidentally detonates inside demilitarization containment chambers are analyzed. The vulnerability of an inner Auxiliary Pressure Vessel and the primary Explosive Containment Chamber to impact by fragments from the largest explosive charge expected to be placed in these chambers (M426, 8 inch, chemical, 7 lbs Comp B) is evaluated. Numerical (CTH) and empirical (ConWep) codes are used to characterize the munition fragments, and assess the consequences of their impact and penetration on the walls of these vessels. Both pristine and corroded configurations of the munition have been considered, with and without liquid agent fill. When the munition burster charge detonates, munition case fragments impact and perforate the Auxiliary Pressure Vessel wall, resulting in extensive breakup of this inner chamber and the formation of additional fragments. These residual munition case and Auxiliary Pressure Vessel fragments have sufficient mass and velocity to crater the Explosive Containment Chamber inner wall layer, with accompanying localized permanent deformation (bulging) of both the inner and outer chamber walls. The integrity of the Explosive Containment Chamber was retained under all of the APV / munition configurations considered in this study, with no evidence that primary (munition) or secondary (munition and Auxiliary Pressure Vessel) fragments will perforate the inner chamber wall. Limited analyses of munition detonation without the Auxiliary Pressure Vessel present indicate that some munition span fragments could form under those conditions that have sufficient mass and velocity to perforate the inner wall of the Explosive Containment Chamber.

Benham, R.A.; Fischer, S.H.; Kipp, M.E.; Martinez, R.R.

1999-02-01

348

Discharge Chamber Primary Electron Modeling Activities in Three-Dimensions  

NASA Technical Reports Server (NTRS)

Designing discharge chambers for ion thrusters involves many geometric configuration decisions. Various decisions will impact discharge chamber performance with respect to propellant utilization efficiency, ion production costs, and grid lifetime. These hardware design decisions can benefit from the assistance of computational modeling. Computational modeling for discharge chambers has been limited to two-dimensional codes that leveraged symmetry for interpretation into three-dimensional analysis. This paper presents model development activities towards a three-dimensional discharge chamber simulation to aid discharge chamber design decisions. Specifically, of the many geometric configuration decisions toward attainment of a worthy discharge chamber, this paper focuses on addressing magnetic circuit considerations with a three-dimensional discharge chamber simulation as a tool. With this tool, candidate discharge chamber magnetic circuit designs can be analyzed computationally to gain insight into factors that may influence discharge chamber performance such as: primary electron loss width in magnetic cusps, cathode tip position with respect to the low magnetic field volume, definition of a low magnetic field region, and maintenance of a low magnetic field region across the grid span. Corroborating experimental data will be obtained from mockup hardware tests. Initially, simulated candidate magnetic circuit designs will resemble previous successful thruster designs. To provide opportunity to improve beyond previous performance benchmarks, off-design modifications will be simulated and experimentally tested.

Steuber, Thomas J.

2004-01-01

349

Liquid Oxygen Cooling of Hydrocarbon Fueled Rocket Thrust Chambers  

NASA Technical Reports Server (NTRS)

Rocket engines using liquid oxygen (LOX) and hydrocarbon fuel as the propellants are being given serious consideration for future launch vehicle propulsion. Normally, the fuel is used to regeneratively cool the combustion chamber. However, hydrocarbons such as RP-1 are limited in their cooling capability. Another possibility for the coolant is the liquid oxygen. Combustion chambers previously tested with LOX and RP-1 as propellants and LOX as the collant demonstrated the feasibility of using liquid oxygen as a coolant up to a chamber pressure of 13.8 MPa (2000 psia). However, there was concern as to the effect on the integrity of the chamber liner if oxygen leaks into the combustion zone through fatigue cracks that may develop between the cooling passages and the hot gas side wall. In order to study this effect, chambers were fabricated with slots machined upstream of the throat between the cooling passage wall and the hot gas side wall to simulate cracks. The chambers were tested at a nominal chamber pressure of 8.6 MPa (1247 psia) over a range of mixture ratios from 1.9 to 3.1 using liquid oxygen as the coolant. The results of the testing showed that the leaking LOX did not have a deleterious effect on the chambers in the region of the slots. However, there was unexplained melting in the throat region of both chambers, but not in line with the slots.

Armstrong, Elizabeth S.

1989-01-01

350

Vacuum Chamber for the Measurement System of the Beam Energy  

NASA Astrophysics Data System (ADS)

Vacuum chamber for the beam energy measurement system based on the Compton backscattering method is presented. The main elements of the chamber are GaAs entrance viewport and a copper mirror. The viewport design provides baking out of the vacuum chamber up to 250 °C. To produce the viewport, an original technology based on brazing GaAs plate by lead has been developed. The vacuum chambers were installed at the BEPC-II and VEPP-4 M colliders. After installation the residual gas pressure is about 10-10 Torr.

Abakumova, E.; Achasov, M.; Dong, HaiYi; Qu, HuaMin; Krasnov, A.; Kosarev, A.; Muchnoi, N.; Pyata, E.; Xiao, Qiong; Mo, XiaoHu; Wang, YiFang; Zhukov, A.

351

4.0 SERVICES PROVIDED BY GREENHOUSE PERSONNEL All plant material receives plant care unless the growth facility user  

E-print Network

the growth facility user requests otherwise. The fee for plant care will be charged even if the user declines request Greenhouse or growth chamber maintenance Routine greenhouse or growth chamber sanitation Plant4.0 SERVICES PROVIDED BY GREENHOUSE PERSONNEL All plant material receives plant care unless

Pawlowski, Wojtek

352

Do open-top chambers overestimate the effects of rising CO2 on plants? An analysis using spring wheat  

Microsoft Academic Search

The microclimate in facilities for studying effects of elevated CO2 on crops differs from ambient conditions. Open-top chambers (OTCs) increase temperature by 1-3 °C. If temper- ature and CO2 interact in their effect on crops, this would limit the value of OTC experi- ments. Furthermore, interaction of CO2 and temperature deserves study because increases in atmospheric CO2 concentration are expected

M. VA N O IJEN; A. H. C. M. S CHAPENDONK; M. J. H. J ANSEN; C. S. P OT; R. M ACIOROWSKI

1999-01-01

353

Do open-top chambers overestimate the effects of rising CO2 on plants? An analysis using spring wheat  

Microsoft Academic Search

The microclimate in facilities for studying effects of elevated CO2 on crops differs from ambient conditions. Open-top chambers (OTCs) increase temperature by 1–3 °C. If temperature and CO2 interact in their effect on crops, this would limit the value of OTC experiments. Furthermore, interaction of CO2 and temperature deserves study because increases in atmospheric CO2 concentration are expected to cause

M. Van Oijen; A. H. C. M. Schapendonk; M. J. H. Jansen; C. S. Pot; R. Maciorowski

1999-01-01

354

Modeling of Solid Waste Flow and Mixing on the Traveling Grate of a Waste-to- energy Combustion Chamber  

Microsoft Academic Search

Mixing of the highly non-homogeneous municipal solid wastes (MSW) on the traveling grate of mass-burn combustion chambers assists the combustion process in waste-to-energy (WTE) facilities. A matrix-based Markov chain model was developed to simulate particle flow and mixing as the solid waste particles travel over a reverse acting Martin grate. The model was used to project the pathway of a

MASATO NAKAMURA; N. J. THEMELIS

355

Quantifying the "chamber effect" in CO2 flux measurements  

NASA Astrophysics Data System (ADS)

The significance of aquatic CO2 emissions has received attention in recent years. For example annual aquatic emissions in the Amazon basin have been estimated as 500 Mt of carbon1. Methods for determining the flux rates include eddy covariance flux tower measurements, flux estimates calculated from partial pressure of CO2 (pCO2) in water and the use floating flux chambers connected to an infra-red gas analyser. The flux chamber method is often used because it is portable, cheaper and allows smaller scale measurements. It is also a direct method and hence avoids problems related to the estimation of the gas transfer coefficient that is required when fluxes are calculated from pCO2. However, the use of a floating chamber may influence the flux measurements obtained. The chamber shields the water underneath from effects of wind which could lead to lower flux estimates. Wind increases the flux rate by i) causing waves which increase the surface area for efflux, and ii) removing CO2 build up above the water surface, hence maintaining a higher concentration gradient. Many floating chambers have an underwater extension of the chamber below the float to ensure better seal to water surface and to prevent any ingress of atmospheric air when waves rock the chamber. This extension may cause additional turbulence in flowing water and hence lead to overestimation of flux rates. Some groups have also used a small fan in the chamber headspace to ensure thorough mixing of air in the chamber. This may create turbulence inside the chamber which could increase the flux rate. Here we present results on the effects of different chamber designs on the detected flux rates. 1Richey et al. 2002. Outgassing from Amazonian rivers and wetlands as a large tropical source of atmospheric CO2. Nature 416: 617-620.

Vihermaa, Leena; Childs, Amy; Long, Hazel; Waldron, Susan

2014-05-01

356

Microwave remote plasma enhanced-atomic layer deposition system with multicusp confinement chamber  

NASA Astrophysics Data System (ADS)

A microwave remote Plasma Enhanced-Atomic Layer Deposition system with multicusp confinement chamber is established at the Plasma and Beam Physics research facilities, Chiang Mai, Thailand. The system produces highly-reactive plasma species in order to enhance the deposition process of thin films. The addition of the multicusp magnetic fields further improves the plasma density and uniformity in the reaction chamber. Thus, the system is more favorable to temperature-sensitive substrates when heating becomes unwanted. Furthermore, the remote-plasma feature, which is generated via microwave power source, offers tunability of the plasma properties separately from the process. As a result, the system provides high flexibility in choice of materials and design experiments, particularly for low-temperature applications. Performance evaluations of the system were carried on coating experiments of Al2O3 layers onto a silicon wafer. The plasma characteristics in the chamber will be described. The resulted Al2O3 films—analyzed by Rutherford Backscattering Spectrometry in channeling mode and by X-ray Photoelectron Spectroscopy techniques—will be discussed.

Dechana, A.; Thamboon, P.; Boonyawan, D.

2014-10-01

357

The Joint Airlock Module is moved to the O&C vacuum chamber  

NASA Technical Reports Server (NTRS)

The Joint Airlock Module swings into position near the top of the Operations and Checkout Building to move toward the vacuum chamber at right. Workers alongside the chamber watch the airlock's progress. The airlock is being tested for leaks. The module is the gateway from which crew members aboard the International Space Station (ISS) will enter and exit the 470-ton orbiting research facility. The airlock is a critical element of the ISS because of design differences between American and Russian spacesuits. The Joint Airlock Module provides a chamber where astronauts from every nation can suit up for space walks to conduct maintenance and construction work or to do science experiments outside the Station. The Space Shuttle Atlantis will carry the airlock to orbit on mission STS-104, the 10th International Space Station flight, currently targeted for liftoff in May 2001. The Shuttle crew will secure the airlock to the right side of Unity, the American-built connecting node that currently comprises one-third of the current Space Station, along with the Russian modules Zarya and Zvezda.

2000-01-01

358

Disequilbrium plagioclase in Icelandic magma chambers  

NASA Astrophysics Data System (ADS)

The Austurhorn intrusive complex of southeast Iceland represents the exhumed roots of a ~6 Ma central volcano. A modally layered gabbro occupies the central part of the complex. The outer part is dominated by granophyre which frequently carries pillow- or sheet-like enclaves of basalt, interpreted to reflect mafic magma intruded into a molten rhyolitic magma chamber. Some of the basaltic pillows are highly plagioclase-phyric (20-30%) and carry macrocrysts with cores that are more primitive (An85-75) than overgrowth rims and groundmass grains (An67-43), indicating disequilibrium with the host melt. The layered gabbro comprises more than 800 m of cpx + plag ± ol ± Fe-Ti oxide cumulates and can be divided into at least 8 macrorhythmic units formed by repeated injections of mafic magma. Two distinct populations of high- and low-An plagioclase crystals have also been identified in the gabbro. The high-An grains are typically 2-4 mm, prismatic to tabular in shape and have bytownite cores (An87-69) abruptly zoned to labradorite rims (An65-55). The low-An grains (An69-55) are smaller (1-2 mm), typically lath-shaped and weakly zoned (?An ? 7 mol.%). Microdrilling followed by TIMS Sr isotope analyses of high- and low-An plagioclase grains indicate that the rims of the high-An grains (87Sr/86Sr = 0.70337-0.70340) are in isotopic equilibrium with the low-An grains (0.70338). The cores of the high-An grains, however, are generally more radiogenic (0.70342-0.70344) than coexisting rims, indicating a xenocrystic origin. We suggest that the high-An plagioclase macrocrysts of the basalt enclaves and the layered gabbro are two of kind and grew in a deeper, more primitive magma chamber. The macrocrysts were entrained by genetically unrelated magmas and were carried into the Austurhorn plumbing system during magma recharge events. The low-An grains, on the other hand, are interpreted to record in situ growth.

Thórarinsson, Sigurjón B.; Tegner, Christian; Waight, Tod E.

2014-05-01

359

Solar Thermal Propulsion Test Facility  

NASA Technical Reports Server (NTRS)

Researchers at the Marshall Space Flight Center (MSFC) have designed, fabricated and tested the first solar thermal engine, a non-chemical rocket engine that produces lower thrust but has better thrust efficiency than a chemical combustion engine. MSFC turned to solar thermal propulsion in the early 1990s due to its simplicity, safety, low cost, and commonality with other propulsion systems. Solar thermal propulsion works by acquiring and redirecting solar energy to heat a propellant. This photograph, taken at MSFC's Solar Thermal Propulsion Test Facility, shows a concentrator mirror, a combination of 144 mirrors forming this 18-ft diameter concentrator, and a vacuum chamber that houses the focal point. The 20- by 24-ft heliostat mirror (not shown in this photograph) has a dual-axis control that keeps a reflection of the sunlight on the 18-foot diameter concentrator mirror, which then focuses the sunlight to a 4-in focal point inside the vacuum chamber. The focal point has 10 kilowatts of intense solar power. As part of MSFC's Space Transportation Directorate, the Propulsion Research Center serves as a national resource for research of advanced, revolutionary propulsion technologies. The mission is to move the Nation's capabilities beyond the confines of conventional chemical propulsion into an era of aircraft-like access to Earth-orbit, rapid travel throughout the solar system, and exploration of interstellar space.

1999-01-01

360

Solar Thermal Propulsion Test Facility  

NASA Technical Reports Server (NTRS)

Researchers at the Marshall Space Flight Center (MSFC) have designed, fabricated, and tested the first solar thermal engine, a non-chemical rocket engine that produces lower thrust but has better thrust efficiency than a chemical combustion engine. MSFC turned to solar thermal propulsion in the early 1990s due to its simplicity, safety, low cost, and commonality with other propulsion systems. Solar thermal propulsion works by acquiring and redirecting solar energy to heat a propellant. This photograph shows a fully assembled solar thermal engine placed inside the vacuum chamber at the test facility prior to testing. The 20- by 24-ft heliostat mirror (not shown in this photograph) has a dual-axis control that keeps a reflection of the sunlight on the 18-ft diameter concentrator mirror, which then focuses the sunlight to a 4-in focal point inside the vacuum chamber. The focal point has 10 kilowatts of intense solar power. As part of MSFC's Space Transportation Directorate, the Propulsion Research Center serves as a national resource for research of advanced, revolutionary propulsion technologies. The mission is to move theNation's capabilities beyond the confines of conventional chemical propulsion into an era of aircraft-like access to Earth orbit, rapid travel throughout the solar system, and exploration of interstellar space.

1999-01-01

361

Boeing infrared sensor (BIRS) calibration facility  

NASA Technical Reports Server (NTRS)

The Boeing Infrared Sensor (BIRS) Calibration Facility represents a major capital investment in optical and infrared technology. The facility was designed and built for the calibration and testing of the new generation large aperture long wave infrared (LWIR) sensors, seekers, and related technologies. Capability exists to perform both radiometric and goniometric calibrations of large infrared sensors under simulated environmental operating conditions. The system is presently configured for endoatmospheric calibrations with a uniform background field which can be set to simulate the expected mission background levels. During calibration, the sensor under test is also exposed to expected mission temperatures and pressures within the test chamber. Capability exists to convert the facility for exoatmospheric testing. The configuration of the system is described along with hardware elements and changes made to date are addressed.

Hazen, John D.; Scorsone, L. V.

1990-01-01

362

EFFECTS OF ACTIVATED CHARCOAL FILTRATION AND OZONATION ON HYDROCARBON AND CARBONYL LEVELS OF AMBIENT AIR USED IN CONTROLLED-EXPOSURE CHAMBER STUDIES OF AIR POLLUTANT HUMAN HEALTH EFFECTS  

EPA Science Inventory

Air sampling experiments were done in 1985, 1987, and 1993 at the human-exposure chamber facility of the U.S. EPA Health Effects Research Laboratory in Chapel Hill, NC. easurements of VOC's by GC-FID and aldehyde measurements by the DNPH silica gel cartridge method were made, com...

363

Growth of Crop and Weeds in Growth Chambers and Outdoors  

Microsoft Academic Search

The early growth of spring barley (Hordeum ulgare L.), Brassica rapa L. ssp. oleifera (DC.) Metzger, Stellaria media (L.) Vill. and Viola arvensis Murray in growth chambers and in shading cages outdoors at different irradiance levels was compared. Leaf area and shoot dry weight were lower outdoors than in growth chambers at similar irradiance and temperature. A simulation model with

Kirsten Semb Tørresen; Lambertus A. P. Lotz

2000-01-01

364

Reaction of a real explosion chamber to internal pulsed loading  

Microsoft Academic Search

Results are given for strain measurements of an actual explosion chamber intended for explosive hardening of railway points with an explosive charge weight up to 20 kg. It is shown that with an increase in explosive weight within the working range average stresses increase linearly. A special point of the construction is the pole of the chamber bottom. Use of

V. V. Sil'vestrov; A. V. Plastinin; N. N. Gorshkov; O. I. Stoyanovskii

1994-01-01

365

Controls on the growth and eruption of large magma chambers  

NASA Astrophysics Data System (ADS)

What controls maximum magma chamber size? Deposits from flood basalts and ignimbrite flare-ups record multiple successive eruptions exceeding 1000 cubic kilometers, suggesting repeated assembly of reservoirs at least this large. Crustal heating through intrusion promotes viscous creep in country rocks, enabling stable growth of the magma chambers required for these eruptions. Numerical simulations show that melt influx rate, depth in the geotherm, and crustal composition exert primary control on chamber growth. But we find that fundamental size limits are imposed by the concentration of deviatoric stresses from the free surface, and chamber failure may be ultimately determined by the strength of crustal rocks. We focus on shallow caldera-forming magma chambers, motivated by the observed distribution of collapse calderas and their deposits on Earth, Mars and Io to study generic controls on chamber size. We develop a numerical model of coupled magma chamber deformation and conduit flow to simulate the coupled fluid and solid mechanics of caldera-forming eruptions. Crustal yield strength is the most important factor determining collapse, with roof aspect ratio and evolving rheology of magma in the chamber also important. We suggest that the largest silicic eruptions require country rocks with yield strength in excess of 100 MPa, which may evolve through thermal annealing of crust by intrusions. We use caldera size distributions to estimate the elastic strength of crust on Earth, Mars and Io.

Karlstrom, L.; Manga, M.; Rudolph, M. L.

2011-12-01

366

Combustion chamber struts can be effectively transpiration cooled  

NASA Technical Reports Server (NTRS)

Vapor-deposited sintering technique increases the feasible temperature range of transpiration-cooled structural members in combustion chambers. This technique produces a porous mass of refractory metal wires around a combustion chamber structural member. This mass acts as a transpiration-cooled surface for a thick-walled tube.

Palmer, G. H.

1966-01-01

367

The Meditation Chamber : A Debriefing A. Fleming Seay  

E-print Network

The Meditation Chamber : A Debriefing A. Fleming Seay HCII Carnegie Mellon University afseay attendees experienced The Meditation Chamber. This immersive, bio-interactive environment was designed and meditation experience. During this sketch, the project's producers will discuss the design and implementation

Shaw, Chris

368

Exciting Internship at the American Arab Chamber of Commerce  

E-print Network

Exciting Internship at the American Arab Chamber of Commerce Take advantage of the opportunity@americanarab.com with the subject "Internship Opportunity." Include a brief statement on why you would like to work at the American Arab Chamber of Commerce, along with your availability. If you are looking for an internship to fulfill

Cinabro, David

369

Damage Diagnosis for High Temperature Coke-oven Chamber Walls  

NASA Astrophysics Data System (ADS)

Metallurgical coke is needed as reducing reagent and energy source in blast furnaces. Most of coke ovens in Japan have been working over 30 years and have become gradually decrepit. A coke oven consists of many coking chambers, and each chamber is 6 m high, 16 m long and 0.4m wide. Uneven damage at the chamber-wall surface such as brick erosion and carbon deposition disturbs production because the coke is pushed horizontally when discharged from the chamber. To diagnose the chamber wall which is constantly sustained at a high temperature, we have developed a water-cooling heat-resistance probe. Line scan cameras mounted in the probe obtain thermal images of the entire chamber-wall surfaces with high resolution. In addition, to measure topographical information of the wall, a laser light-section method combined with line-scan-camera imaging has been considered. It is emphasized that the diagnosis probe works under enormously severe conditions, such as at a temperature of over 1000°C and inside a width of only 0.4m. Clarifying the appearance of chamber-wall damages in operating aged coke ovens, we proposed the index relating unevenness of a chamber-wall surface to pushing load. The index is utilized for the guidance enabling effective repairs of damaged oven walls.

Sugiura, Masato; Sakaida, Michitaka; Fujikake, Yohichi; Irie, Keisuke

370

Prediction of temperature front in a gas turbine combustion chamber  

Microsoft Academic Search

Numerical computation has been applied to investigate the temperature field in a gas turbine combustion chamber. The simulation assumed that pressure imbalance conditions of air flow between primary and secondary inlets occur. The combustion chamber under study is part of a 70MW gas turbine from an operating combined cycle power plant. The combustion was simulated with normal fuel–air flow rate

F. Z. Sierra; J. Kubiak; G. González; G. Urquiza

2005-01-01

371

Optimization of Hot Gas Chamber in High Temperature Reactor  

Microsoft Academic Search

The flow field in the hot gas chamber of the High Temperature Gas Cooled Reactor (HTGCR) was studied with the Computational Fluid Dynamics (CFD) program CFX5. On the basis of the experimental studies, the velocity field, pressure field and temperature field in the hot gas chamber and hot gas duct were obtained, and the simulation's accuracy and reliability were validated

Jinhua WANG; Hanliang BO; Shengyao JIANG; Yuanhui XU; Wenxiang ZHENG

2004-01-01

372

The major parameters affecting temperature inside inhalation chambers  

Microsoft Academic Search

Variations in inhalation chamber temperature can produce alterations in animal physiology, metabolism of foreign compounds as well as the chemical interaction of pollutant aerosols. This report presents the results of an investigation of the different mechanisms of heat transfer in a 380?L inhalation chamber and discusses the relative effectiveness of various methods that may be used to maintain a uniform

DAVID M. BERNSTEIN; ROBERT T. DREW

1980-01-01

373

Thermoelectric Cloud Chamber Showing Charged Subatomic Particle Tracks  

NASA Astrophysics Data System (ADS)

Alpha particle tracks can be photographed and their lengths measured in an introductory laboratory using this thermoelectrically cooled diffusion cloud chamber. Without a radioactive source, cosmic ray tracks can be observed. Ice water is used to cool the Peltier device (about 1 kg of ice per hour). Good tracks are observed within half an hour after the cloud chamber is turned on.

Rowland, S. Clark; Lee, B. E.

2007-05-01

374

Thermoelectric Cloud Chamber Showing Charged Subatomic Particle Tracks  

Microsoft Academic Search

Alpha particle tracks can be photographed and their lengths measured in an introductory laboratory using this thermoelectrically cooled diffusion cloud chamber. Without a radioactive source, cosmic ray tracks can be observed. Ice water is used to cool the Peltier device (about 1 kg of ice per hour). Good tracks are observed within half an hour after the cloud chamber is

S. Clark Rowland; B. E. Lee

2007-01-01

375

Idea Bank: Chamber Music within the Large Ensemble  

ERIC Educational Resources Information Center

Many music educators incorporate chamber music in their ensemble programs--an excellent way to promote musical independence. However, they rarely think of the large ensemble as myriad chamber interactions. Rehearsals become more productive when greater responsibility for music-making is placed on the individual student. This article presents some…

Neidlinger, Erica

2011-01-01

376

Design handbook for gaseous fuel engine injectors and combustion chambers  

NASA Technical Reports Server (NTRS)

Results of investigation of injection, mixing, and combustion processes using gaseous fuels and oxidizers have been summarized in handbook presenting succinct design procedures for injectors and methods for estimating combustion efficiency, chamber heat flux and stability characteristics. Handbook presents two approaches to injector and combustion chamber design: empirical and analytical.

Calhoon, D. F.; Ito, I.; Kors, D. L.

1973-01-01

377

November 8-9, 2005 Blanket Design for Large Chamber  

E-print Network

History and Gradient · W temperature at different locations as a f(time) · W temperature profile in armor We Have Chosen a Reference Case for the Large Chamber Approach with No Protective Gas · Reference Parameters: for no chamber gas and assumed constraint of W Tmax

Raffray, A. René

378

MODEL IV-GRAPHITE, CARBON DIOXIDE 4CC IONIZATION CHAMBER  

Microsoft Academic Search

The Model IV 4-cc ionization chamber, a graphite-COâ chamber ; filled with 99.99% pure COâ to a pressure of 30 in. Hg, was designed to ; withstand mechanical vibration as well as high gamma dose rates. The materials ; used were selected for long life in high radiation fields and for low neutron ; activation. To determine saturation characteristics, the

C. C. Hall; S. D. Johnson

1960-01-01

379

Photocopy of drawing. ALTITUDE CHAMBERS ?L? & ?R? STRUCTURES. NASA, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Photocopy of drawing. ALTITUDE CHAMBERS ?L? & ?R? STRUCTURES. NASA, John F. Kennedy Space Center, Florida. Drawing 68-K-L-11213, NASA KSC, March, 1971. DOOR LATCH MECHANISM & DOOR LATCHING RATCHET. Sheet 14 - Cape Canaveral Air Force Station, Launch Complex 39, Altitude Chambers, First Street, between Avenue D and Avenue E, Cape Canaveral, Brevard County, FL

380

Photocopy of drawing. ALTITUDE CHAMBERS ?L? & ?R? STRUCTURES. NASA, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Photocopy of drawing. ALTITUDE CHAMBERS ?L? & ?R? STRUCTURES. NASA, John F. Kennedy Space Center, Florida. Drawing 68-K-L-11213, NASA KSC, November, 1968. WORK PLATFORM DETAIL. Sheet 6 - Cape Canaveral Air Force Station, Launch Complex 39, Altitude Chambers, First Street, between Avenue D and Avenue E, Cape Canaveral, Brevard County, FL

381

Heat pipe technology for advanced rocket thrust chambers  

NASA Technical Reports Server (NTRS)

The application of heat pipe technology to the design of rocket engine thrust chambers is discussed. Subjects presented are: (1) evaporator wick development, (2) specific heat pipe designs and test results, (3) injector design, fabrication, and cold flow testing, and (4) preliminary thrust chamber design.

Rousar, D. C.

1971-01-01

382

THE CARBON DIOXIDE LEAKAGE FROM CHAMBERS MEASURED USING SULFUR HEXAFLUORIDE  

EPA Science Inventory

In plant chamber studies, if Co2 leaking from a chamber is not quantified, it can lead to an overestimate of assimilation rates and an underestimate of respiration rates: consequently, it is critical that Co2 leakage be determined. Sulfur Hexafluoride (SF6) was introduced into t...

383

A novel experimental hypoxia chamber for cell culture  

PubMed Central

Tissue hypoxia is a common pathophysiological process. Since 1990s, numerous studies have focused on investigating cellular adaptation to experimental hypoxia. A modular incubator chamber made of solid materials has frequently been used in the experiments that require hypoxic conditions. Here, we introduce a novel and inflatable chamber for hypoxia experiments. In experiments detecting hypoxia-induced accumulation of hypoxia-inducible factor 1? (HIF-1?) and hypoxia-induced expression of HIF-1-regulated genes, the new chamber yielded reproducible and comparable results as the modular incubator chamber did. The new chamber did not create inner chamber pressure during its use. Other properties of the new chamber were low-cost, easy to use, and leakage-free. Moreover, the size of the new chamber was adjustable, and the smaller one could be placed onto an inverted microscope for real-time studies. The successful examples of real-time studies included the real-time recording of GFP-HIF-1? fusion nuclear translocation and endothelial cell tubular formation. PMID:24482738

Wang, Ruoxiang; Jin, Fengshuo; Zhong, Hua

2014-01-01

384

Gas and aerosol wall losses in Teflon film smog chambers  

Microsoft Academic Search

Large smog chambers (approx.60 m³) constructed of FEP Teflon film are frequently used to study photochemistry and aerosol formation in model chemical systems. In a previous paper a theory for aerosol wall loss rates in Teflon film smog chambers was developed; predicted particle loss rates were in good agreement with measured rates. In the present paper, measurements of wall deposition

Peter H. McMurry; Daniel Grosjean

1985-01-01

385

Dark Matter Time Projection Chamber: Recent R&D Results  

Microsoft Academic Search

The Dark Matter Time Projection Chamber collaboration recently reported a dark matter limit obtained with a 10 liter time projection chamber filled with CF4 gas. The 10 liter detector was capable of 2D tracking (perpendicular to the drift direction) and 2D fiducialization, and only used information from two CCD cameras when identifying tracks and rejecting backgrounds. Since that time, the

J. B. R. Battat; S. Ahlen; M. Chernicoff; C. Deaconu; D. Dujmic; A. Dushkin; P. Fisher; S. Henderson; A. Inglis; A. Kaboth; L. Kirsch; J. P. Lopez; J. Monroe; H. Ouyang; G. Sciolla; H. Tomita; H. Wellenstein

2011-01-01

386

R3B time projection chamber  

NASA Astrophysics Data System (ADS)

Within the international FAIR project, the R3B collaboration (Reaction studies with Radioactive Relativistic beams) will be in charge of the physics program with secondary beams of energy between 200 and 1500MeV per nucleon. Central to the R3B set-up will be a large-aperture superconducting magnet under construction at CEA-Saclay. An international collaboration has been formed to work on the design of a large time-projection chamber (TPC) to be installed behind this magnet to cover the full phase-space of the charged fragments produced in the target. Within this collaboration, tests of detector prototypes were performed with the heavy-ions beams at GSI Darmstadt. These prototypes were equipped with a gaseous Micromegas detector. Two amplification technologies were tested, either conventional or resistive Micromegas and two construction concepts, bulk-Micromegas or micro-meshes screwed on the PCB. We will present the results of the last beam and the 1m TPC station which will be dedicated to make tests using the real drift distance and compare the performances of micromegas and GEM.

Legou, P.

2012-07-01

387

Chemistry of radiation damage to wire chambers  

SciTech Connect

Proportional counters are used to study aspects of radiation damage to wire chambers (wire aging). Principles of low-pressure, rf plasma chemistry are used to predict the plasma chemistry in electron avalanches (1 atm, dc). (1) Aging is studied in CF{sub 4}/iC{sub 4}H{sub 10} gas mixtures. Wire deposits are analyzed by Auger electron spectroscopy. An apparent cathode aging process resulting in loss of gain rather than in a self-sustained current is observed in CF{sub 4}-rich gases. A four-part model considering plasma polymerization of the hydrocarbon, etching of wire deposits by CF{sub 4}, acceleration of deposition processes in strongly etching environments, and reactivity of the wire surface is developed to understand anode wire aging in CF{sub 4}/iC{sub 4}H{sub 10} gases. Practical guidelines suggested by the model are discussed. (2) Data are presented to suggest that trace amounts of Freons do not affect aging rates in either dimethyl ether or Ar/C{sub 2}H{sub 6}. Apparent loss of gain is explained by attachment of primary electrons to a continuously increasing concentration of Freon 11 (CCl{sub 3}F) in the counter gas. An increase in the concentration of Freon 11 in dimethyl ether is caused by a distillation process in the gas supply bottle and is a natural consequence of the unequal volatilities of the two compounds.

Wise, J.

1992-08-01

388

Performance of large area Micro Pixel Chamber  

E-print Network

A novel gaseous two-dimensional imaging detector "Micro Pixel Chamber (micro-PIC)" has been developed. This detector is based on double sided printed circuit board (PCB). We have developed large area (10cm x 10cm) micro-PICs with 65536 pixel anodes of 400um pitch on a 100um thick insulating substrate. Achieved energy resolution was 30% (FWHM) at 5.9keV, and a gas gain of 7000 was obtained with argon ethane (8:2) gas mixture. This gain is high enough to detect minimum ionizing particles with such a small electrode pitch. Although several discharges occurred during 65 hours continuous operation, the detectors have kept stable operation with high gain. The micro-PIC is a useful detector for many applications e.g. X-ray, gamma ray, and charged particle imaging. The micro electrode structure allows us to measure directions of primary electrons due to incident X-rays or gamma rays, which provide a strong method for X-ray polarimetry and gamma-ray imaging.

T. Nagayoshi; H. Kubo; K. Miuchi; A. Ochi; R. Orito; A. Takada; T. Tanimori; M. Ueno

2003-01-09

389

Performance of large area Micro Pixel Chamber  

NASA Astrophysics Data System (ADS)

A novel gaseous two-dimensional imaging detector "Micro Pixel Chamber (?-PIC)" has been developed. This detector is based on double sided printed circuit board (PCB). We have developed large area (10 cm×10 cm) ?-PICs with 65536 pixel anodes of 400 ?m pitch on a 100 ?m thick insulating substrate. Achieved energy resolution was 30% (FWHM) at 5.9 keV, and a gas gain of 7000 was obtained with argon ethane (8:2) gas mixture. This gain is high enough to detect minimum ionizing particles with such a small electrode pitch. Although several discharges occurred during 65 h continuous operation, the detectors have kept stable operation with high gain. The ?-PIC is a useful detector for many applications e.g. X-ray, gamma ray, and charged particle imaging. The micro electrode structure allows us to measure directions of primary electrons due to incident X-rays or gamma rays, which provide a strong method for X-ray polarimetry and gamma-ray imaging.

Nagayoshi, Tsutomu; Kubo, Hidetoshi; Miuchi, Kentaro; Ochi, Atsuhiko; Orito, Reiko; Takada, Atsushi; Tanimori, Toru; Ueno, Masaru

2003-11-01

390

A very large area Micro Pixel Chamber  

NASA Astrophysics Data System (ADS)

A Micro Pixel Chamber, called " ?-PIC", is a gaseous 2D imaging detector with a fine pixel electrode based on the Printed Circuit Board technology, and we developed it for the X/gamma-ray imaging and the tracking of the charged particles [A. Ochi, et al., Nucl. Instr. and Meth. A 478 (2002) 196; T. Nagayoshi, et al., Nucl. Instr. and Meth. A 525 (2004) 20.]. The previous ?-PIC has a fine position resolution, a high gas gain, a good gas gain uniformity and the stable operation. Although the detection area of the previous ?-PIC (˜10×10 cm2) is not large enough for a variety of the application, for example an MeV gamma-ray Compton camera [T. Tanimori, et al., New Astron. Rev. 48 (2004) 263.] and dark matter search [T. Tanimori, et al., Phys. Lett. B 578 (2004) 241.]. Therefore, we developed a new ?-PIC having a ˜30×30 cm2 detection area. The structure and the pitch of the electrode are same as those of the previous ?-PIC. There are 768×768 pixels in the whole area. This ?-PIC (TOSHIBA SN041129-1) is operated with a stable gas gain of ˜3500 and a maximum gain of ˜7000 at the center region, and the variety of the gain was 16.7% RMS. An X-ray image of the whole area was also taken by the irradiation of the X-rays from 109Cd (22 keV) to the whole detection area.

Takada, A.; Hattori, K.; Kabuki, S.; Kubo, H.; Miuchi, K.; Nagayoshi, T.; Nishimura, H.; Okada, Y.; Orito, R.; Sekiya, H.; Takeda, A.; Tanimori, T.; Ueno, K.

2007-04-01

391

Ionization chamber response in intensity-modulated radiotherapy beams  

NASA Astrophysics Data System (ADS)

The response of ionization chambers in IMRT fields has been investigated. Differences between measured and calculated values of average chamber dose associated with chamber position, volume averaging and low monitor unit effects were assessed with regards to patient specific IMRT quality assurance (QA). Calculations were performed with a commercially available treatment planning system (TPS). Inaccuracy of chamber positioning during QA was shown to adversely affect measurements due to steep dose gradients in the vicinity of penumbras generated by MLC leaf-tips. The measurement error was inversely related to chamber size. The Exradin A12 chamber showed errors of 4.1% and 9.6% in its short (0.61 cm) and long dimensions (2.2 cm) while the Exradin T14 Microchamber showed an error of 15.4% in its useful dimension (0.1 cm). A QA phantom was designed to improve positional accuracy and reproducibility. Setup reproducibility results showed a standard deviation of 0.93 and 1.1 mm in the longitudinal and lateral directions through the use of this phantom. The effect of leaf shadowing of a measurement chamber during IMRT QA was correlated to the error in point dose results. The error between calculation and measurement increased with a higher degree of chamber shadowing, which indicated that point dose results could be improved by placing the chamber in areas where the effect of shadowing was minimized. A linear systems approach was utilized to determine the chamber response function of three chambers for subsequent implementation in a TPS. Improvement in dose calculation accuracy was expected. The response functions were used in a TPS to design special chambers that had the same averaging properties as exhibited during water phantom measurements. Results were improved over using a chamber represented by a perfect cylinder, but spatial resolution limitations prevented optimal results. Another chamber design that was based on a heuristic approach yielded desired results with static beam penumbras but was not optimal when used with IMRT fields. Low numbers of monitor units delivered during each subfield of an IMRT treatment can force the linac control system to skip segments which introduces dosimetric error. For individual IMRT fields this effect accounted for an error of up to +/-4%. It was found that most of this error possesses a degree of randomness that is expected to cancel over the delivery of all fields in a clinical situation.

Markovic, Alexander

392

A mechanical mode-stirred reverberation chamber with chaotic geometry  

E-print Network

A previous research on multivariate approach to the calculation of reverberation chamber correlation matrices is used to calculate the number of independent positions in a mode-stirred reverberation chamber. Anomalies and counterintuitive behavior are observed in terms of number of correlated matrix elements with respect to increasing frequency. This is ascribed to the regular geometry forming the baseline cavity (screened room) of a reverberation chamber, responsible for localizing energy and preserving regular modes (bouncing ball modes). Smooth wall deformations are introduced in order to create underlying Lyapunov instability of rays and then destroy survived regular modes. Numerical full-wave simulations are performed for a reverberation chamber with corner hemispheres and (off-)center wall spherical caps. Field sampling is performed by moving a mechanical carousel stirrer. It is found that wave-chaos inspired baseline geometries improve chamber performances in terms of lowest usable frequencies and number of independent cavity realizations of mechanical stirrers.

Gabriele Gradoni; Franco Moglie; Valter Mariani Primiani

2014-07-06

393

Cooling of High Pressure Rocket Thrust Chambers with Liquid Oxygen  

NASA Technical Reports Server (NTRS)

An experimental program using hydrogen and oxygen as the propellants and supercritical liquid oxygen (LOX) as the coolant was conducted at 4.14 and 8.274 MN/square meters (600 and 1200 psia) chamber pressure. Data on the following are presented: the effect of LOX leaking into the combustion region through small cracks in the chamber wall; and verification of the supercritical oxygen heat transfer correlation developed from heated tube experiments; A total of four thrust chambers with throat diameters of 0.066 m were tested. Of these, three were cyclically tested to 4.14 MN/square meters (600 psia) chamber pressure until a crack developed. One had 23 additional hot cycles accumulated with no apparent metal burning or distress. The fourth chamber was operated at 8.274 MN/square meters (1200 psia) pressure to obtain steady state heat transfer data. Wall temperature measurements confirmed the heat transfer correlation.

Price, H. G.

1980-01-01

394

Method for measuring anterior chamber volume by image analysis  

NASA Astrophysics Data System (ADS)

Anterior chamber volume (ACV) is very important for an oculist to make rational pathological diagnosis as to patients who have some optic diseases such as glaucoma and etc., yet it is always difficult to be measured accurately. In this paper, a method is devised to measure anterior chamber volumes based on JPEG-formatted image files that have been transformed from medical images using the anterior-chamber optical coherence tomographer (AC-OCT) and corresponding image-processing software. The corresponding algorithms for image analysis and ACV calculation are implemented in VC++ and a series of anterior chamber images of typical patients are analyzed, while anterior chamber volumes are calculated and are verified that they are in accord with clinical observation. It shows that the measurement method is effective and feasible and it has potential to improve accuracy of ACV calculation. Meanwhile, some measures should be taken to simplify the handcraft preprocess working as to images.

Zhai, Gaoshou; Zhang, Junhong; Wang, Ruichang; Wang, Bingsong; Wang, Ningli

2007-12-01

395

Variable g- Mars environmental chamber: a small window of the martian environment for life science investigations  

NASA Astrophysics Data System (ADS)

Human exploration and permanent settlement on the Martian surface is the one of the most attractive and ambitious endeavors mankind has ever faced. As technology and research progress, solutions and information that were before unavailable are slowly making the dream become everyday more feasible. In the past years a huge amount of knowledge was gathered by the Mars Exploration Rovers Spirit and Opportunity and now, even more insight is being gathered through the latest rover of the family, Curiosity. In this work, data from the various missions will be used to define and reproduce on Earth the characteristic Martian atmospheric conditions. A small Mars environmental chamber has been designed and built with the objective of studying the effects of the Martian environment on biological systems. The Variable gravity Mars Environmental Chamber (VgMEC) will allow researchers to replicate atmospheric pressure, gas composition, temperature and UVA/B exposure typical of the equatorial regions of Mars. By exposing biological systems to a controllable set of stressor it will be possible to identify both multi and single stressor effects on the system of interest. While several Mars environment simulation facilities exist, due to their size and mass, all are confined to floor-fixed laboratory settings. The VgMEC is an OHB funded project that wishes to bring together the scientific community and the industry. Collaborations will be enabled by granting low cost access to cutting-edge instrumentation and services. Developed at OHB System AG, VgMEC has been designed from the ground up to be a 28L, compact and lightweight test volume capable of being integrated in existing centrifuges (such as the ESA-ESTEC LCD), gimbal systems and parabolic flight aircraft. The VgMEC support systems were designed to accommodate continuous operations of virtually unlimited duration through the adoption of solutions such as: hot swappable gas/liquid consumables bottles, low power requirements, an observation window and robust embedded electronics. VgMEC is a new-generation chamber equipped with state-of-the-art contactless sensors and actuators, which can be controlled and monitored remotely allowing the system to be used without requiring the user to be physically in front of the experiential setup. The chamber is also equipped with a load lock system, which allows samples to be placed in the main chamber without breaking its environmental condition and so avoiding the samples experiencing vacuum during the chamber filling phase. Lastly while the VgMEC has been designed specifically for biological systems, its core properties allow alternative sample analysis therefore providing an extremely flexible, accurate, controllable and low-cost alternative for scientific research and Mars flight hardware evaluation.

Sgambati, Antonella; Slenzka, Klaus; Schmeyers, Bernd; Di Capua, Massimiliano; Harting, Benjamin

396

Active Target-Time Projection Chambers for Reactions Induced by Rare Isotope Beams: Physics and Technology  

NASA Astrophysics Data System (ADS)

Weakly bound nuclear systems can be considered to represent a good testing-ground of our understanding of non-perturbative quantum systems. Great progress in experimental sensitivity has been attained by increase in rare isotope beam intensities and by the development of new high efficiency detectors. It is now possible to study reactions leading to bound and unbound states in systems with very unbalanced neutron to proton ratios. Application of Active Target-Time Projection Chambers to this domain of physics will be illustrated by experiments performed with existing detectors. The NSCL is developing an Active Target-Time Projection Chamber (AT-TPC) to be used to study reactions induced by rare isotope beams at the National Superconducting Cyclotron Facility (NSCL) and at the future Facility for Rare Isotope Beams (FRIB). The AT-TPC counter gas acts as both a target and detector, allowing investigations of fusion, isobaric analog states, cluster structure of light nuclei and transfer reactions to be conducted without significant loss in resolution due to the thickness of the target. The high efficiency and low threshold of the AT-TPC will allow investigations of fission barriers and giant resonances with fast fragmentation rare isotope beams. This detector type needs typically a large number of electronic channels (order of magnitude 10,000) and a high speed DAQ. A reduced size prototype detector with prototype electronics has been realized and used in several experiments. A short description of other detectors of this type under development will be given.

Mittig, Wolfgang

2013-04-01

397

Energy Systems Test Area (ESTA). Power Systems Test Facilities  

NASA Technical Reports Server (NTRS)

This viewgraph presentation provides a detailed description of the Johnson Space Center's Power Systems Facility located in the Energy Systems Test Area (ESTA). Facilities and the resources used to support power and battery systems testing are also shown. The contents include: 1) Power Testing; 2) Power Test Equipment Capabilities Summary; 3) Source/Load; 4) Battery Facilities; 5) Battery Test Equipment Capabilities Summary; 6) Battery Testing; 7) Performance Test Equipment; 8) Battery Test Environments; 9) Battery Abuse Chambers; 10) Battery Abuse Capabilities; and 11) Battery Test Area Resources.

Situ, Cindy H.

2010-01-01

398

Beam Test Data Analysis of the Beam Test Data Analysis of the JLCCDC baby Chamber JLCCDC baby Chamber  

Microsoft Academic Search

Studying the higgs boson needs a high resolution tracker. The baby chamber was fabricated with the same cell structure as the current design of the central drift chamber of the Joint Linear Collider. Its performance is studied by looking at the wire efficiency, spatial resolution and twotrack separation capability using an analysis software package already incorporated into the Joint Linear

H. Goo; D. Arogancia; J. Magallanes; A. Bacal; K. Fujii

399

NASA Glenn Research Center Creek Road Complex—Cryogenic Testing Facilities  

NASA Astrophysics Data System (ADS)

Due to expansion at neighboring Cleveland Hopkins Airport, several NASA Glenn Research Center (GRC) facilities have been relocated to the Creek Road Complex. The complex consists of the Small Scale Multi-purpose Research Facility (SMiRF), Cryogenic Components Lab Cell 7 (CCL-7), and a shop building. The facilities have been updated and include state-of-the art technology. SMiRF is a liquid hydrogen/liquid nitrogen (LH 2/LN 2) test facility used to conduct research in a 7400 L vacuum chamber. The chamber simulates space environment and launch vehicle ascent profile. SMiRF handles 5680 L of LH 2. CCL is a LH 2/LN 2 facility to perform small scale proof of concept tests for components and processes. It handles 1130 L of liquid hydrogen. Both facilities handle cryogens at sub-atmospheric pressures.

Jurns, John M.; Kudlac, Maureen T.

2006-02-01

400

Explosive components facility certification tests  

SciTech Connect

Sandia National Laboratories has recently completed construction of a new Explosive Components Facility (ECF) that will be used for the research and development of advanced explosives technology. The ECF includes nine indoor firing pads for detonating explosives and monitoring the detonations. Department of Energy requirements for certification of this facility include detonation of explosive levels up to 125 percent of the rated firing pad capacity with no visual structural degradation resulting from the explosion. The Explosives Projects and Diagnostics Department at Sandia decided to expand this certification process to include vibration and acoustic monitoring at various locations throughout the building during these explosive events. This information could then be used to help determine the best locations for noise and vibration sensitive equipment (e.g. scanning electron microscopes) used for analysis throughout the building. This facility has many unique isolation features built into the explosive chamber and laboratory areas of the building that allow normal operation of other building activities during explosive tests. This paper discusses the design of this facility and the various types of explosive testing performed by the Explosives Projects and Diagnostics Department at Sandia. However, the primary focus of the paper is directed at the vibration and acoustic data acquired during the certification process. This includes the vibration test setup and data acquisition parameters, as well as analysis methods used for generating peak acceleration levels and spectral information. Concerns over instrumentation issues such as the choice of transducers (appropriate ranges, resonant frequencies, etc.) and measurements with long cable lengths (500 feet) are also discussed.

Dorrell, L.; Johnson, D. [Sandia National Labs., Albuquerque, NM (United States)

1995-08-01

401

Aspheric versus Spherical Posterior Chamber Intraocular Lenses  

PubMed Central

Purpose To compare spherical aberration and contrast sensitivity function following implantation of four different foldable posterior chamber intraocular lenses (IOLs), namely Sensar, Akreos AO, Tecnis, and AcrySof IQ. Methods In this randomized clinical trial, 68 eyes of 68 patients with senile cataracts underwent phacoemulsification and IOL implantation with Sensar (n=17), Akreos AO (n=17), Tecnis (n=17), or AcrySof IQ (n=17). Uncorrected visual acuity (UCVA) and best spectacle-corrected visual acuity (BSCVA), spherical aberration and contrast sensitivity function (CSF) were compared among the study groups, 3 months after surgery. Results There was no significant difference between the study groups in terms of age (P = 0.21). Mean postoperative BSCVA with Sensar, Akreos AO, Tecnis, and AcrySof IQ was 0.15±0.10, 0.12±0.9, 0.08±0.08, and 0.08±0.07 logMAR, respectively (P=0.08). Spherical aberration measured over a 4 mm pupil was significantly higher with Sensar and Akreos AO than the two other IOLs. The difference between Tecnis and AcrySof IQ was significantly in favor of the former IOL. Over a 6 mm pupil, spherical aberrations were comparable with Sensar and Akreos AO, furthermore spherical aberration was also comparable among eyes implanted with Akreos AO, AcrySof IQ, and Tecnis. Sensar yielded significantly inferior results as compared to Acrysof IQ and Tecnis. CSF with Sensar was inferior to the three aspheric IOLs at the majority of spatial frequencies. Tecnis yielded significantly better mesopic CSF at 1.5 and 3 cycles per degree spatial frequencies. Conclusion Tecnis and AcrySof IQ provided significantly better visual function as compared to Sensar and Akreos AO, especially with smaller pupil size. However, this difference diminished with increasing pupil size. PMID:22737364

Jafarinasab, Mohammad-Reza; Feizi, Sepehr; Baghi, Ahmad-Reza; Ziaie, Hossein; Yaseri, Mehdi

2010-01-01

402

Validation of High Aspect Ratio Cooling in a 89 kN (20,000 lb(sub f)) Thrust Combustion Chamber  

NASA Technical Reports Server (NTRS)

In order to validate the benefits of high aspect ratio cooling channels in a large scale rocket combustion chamber, a high pressure, 89 kN (20,000 lbf) thrust, contoured combustion chamber was tested in the NASA Lewis Research Center Rocket Engine Test Facility. The combustion chamber was tested at chamber pressures from 5.5 to 11.0 MPa (800-1600 psia). The propellants were gaseous hydrogen and liquid oxygen at a nominal mixture ratio of six, and liquid hydrogen was used as the coolant. The combustion chamber was extensively instrumented with 30 backside skin thermocouples, 9 coolant channel rib thermocouples, and 10 coolant channel pressure taps. A total of 29 thermal cycles, each with one second of steady state combustion, were completed on the chamber. For 25 thermal cycles, the coolant mass flow rate was equal to the fuel mass flow rate. During the remaining four thermal cycles, the coolant mass flow rate was progressively reduced by 5, 6, 11, and 20 percent. Computer analysis agreed with coolant channel rib thermocouples within an average of 9 percent and with coolant channel pressure drops within an average of 20 percent. Hot-gas-side wall temperatures of the chamber showed up to 25 percent reduction, in the throat region, over that of a conventionally cooled combustion chamber. Reducing coolant mass flow yielded a reduction of up to 27 percent of the coolant pressure drop from that of a full flow case, while still maintaining up to a 13 percent reduction in a hot-gas-side wall temperature from that of a conventionally cooled combustion chamber.

Wadel, Mary F.; Meyer, Michael L.

1996-01-01

403

A mission profile life test facility. [for mercury ion thrusters  

NASA Technical Reports Server (NTRS)

A test facility is being prepared for a 16,000 hour mission profile life test of multiple electric propulsion thrust subsystems. The facility will be capable of simultaneously operating three 2.7 kW, 30 cm mercury ion thrusters and their power processing. The facility will permit conduction of a program of long-term tests to document thruster characteristics as a function of time and operating point to allow prediction of thruster performance for any mission profile. The thruster will be tested in a 7m by 10m vacuum chamber. Each thruster will be installed in a separate lock chamber so that it can be extended into, or extracted from the main chamber without violating the vacuum integrity of the other thruster. The thrusters will exhaust into a 3m by 5m frozen mercury target. The target and an array of cryopanels to collect sputtered target material will be liquid nitrogen chilled. Power processor units will be tested in an adjacent 1.5m by 2m vacuum chamber and will be temperature controlled by simulated heat pipes.

James, E.; Vetrone, R.; Bechtel, R.

1978-01-01

404

Facilities Planning & Management FACILITIES PLANNING & MANAGEMENT  

E-print Network

Facilities Planning & Management FACILITIES PLANNING & MANAGEMENT Associate Executive Director Geoffrey Ellazar Shuttle Drivers Budget Manager Caren Johnson Admin.Analyst I Mikki Comstock Senior Property Manager Deborah Collet Mike Johnson Rick Sims Building Maintenance Workers Admin. Support Asst. I

Ponce, V. Miguel

405

Autoignition Chamber for Remote Testing of Pyrotechnic Devices  

NASA Technical Reports Server (NTRS)

The autoignition chamber (AIC) performs by remotely heating pyrotechnic devices that can fit the inner diameter of the tube furnace. Two methods, a cold start or a hot start, can be used with this device in autoignition testing of pyrotechnics. A cold start means extending a pyrotechnic device into the cold autoignition chamber and then heating the device until autoignition occurs. A hot start means heating the autoignition chamber to a specified temperature, and then extending the device into a hot autoignition chamber until autoignition occurs. Personnel are remote from the chamber during the extension into the hot chamber. The autoignition chamber, a commercially produced tubular furnace, has a 230-V, single-phase, 60-Hz electrical supply, with a total power output of 2,400 W. It has a 6-in. (15.2-cm) inner diameter, a 12-in. (30.4-cm) outer diameter and a 12-in.- long (30.4-cm), single-zone, solid tubular furnace (element) capable of heating to temperatures up to 2,012 F (1,100 C) in air.

Harrington, Maureen L.; Steward, Gerald R.; Dartez, Toby W.

2009-01-01

406

A microperfusion chamber for study of mammalian spermatozoa.  

PubMed

The design of a microperfusion chamber is presented for use with spermatozoa or other cell suspensions. This chamber allows perfusion of a small number of spermatozoa during simultaneous observation of cell behavior at the microscope. The chamber is made from a flat glass capillary tube that is fitted at both ends with a filter unit containing Millipore filter discs. The entire assembly is designed to fit the stage of an inverted microscope. A population containing as few as several hundred sperm cells may be observed in the chamber during successive changes of the suspending medium as controlled by a perfusion pump. Several experiments are presented demonstrating sperm survival in the sealed chamber and the response of rabbit and human sperm motility after the washing process. For these manipulations, the percentage of motile cells, linear swimming speed and incidence of hyperactivated motility are reported. Simple incubation in the chamber for 1 hour was not deleterious to the motility of rabbit spermatozoa. Human seminal spermatozoa showed no decline in vigorous motility after the washing procedure. Compared with in vitro capacitated spermatozoa, however, washing of rabbit seminal spermatozoa showed a variable response. Finally, partially capacitated human spermatozoa were examined for any alteration of motility during chamber incubation with a subsequent wash. When small numbers of spermatozoa or other cell types must be manipulated, the methodology can be effectively substituted for the standard washing procedure that uses repeated centrifugation and resuspension. PMID:3384740

Burkman, L J

1988-01-01

407

Performance of Several Combustion Chambers Designed for Aircraft Oil Engines  

NASA Technical Reports Server (NTRS)

Several investigations have been made on single-cylinder test engines to determine the performance characteristics of four types of combustion chambers designed for aircraft oil engines. Two of the combustion chambers studied were bulb-type precombustion chambers, the connecting orifice of one having been designed to produce high turbulence by tangential air flow in both the precombustion chamber and the cylinder. The other two were integral combustion chambers, one being dome-shaped and the other pent-roof shaped. The injection systems used included cam and eccentric driven fuel pumps, and diaphragm and spring-loaded fuel-injection valves. A diaphragm type maximum cylinder pressure indicator was used in part of these investigations with which the cylinder pressures were controlled to definite valves. The performance of the engines when equipped with each of the combustion chambers is discussed. The best performance for the tests reported was obtained with a bulb-type combustion chamber designed to give a high degree of turbulence within the bulb and cylinder. (author)

Joachim, William F; Kemper, Carlton

1928-01-01

408

Calibration of photon and electron beams with an extrapolation chamber.  

PubMed

A variable air-volume, parallel-plate extrapolation chamber forming an integral part of a Solid Water phantom was built to determine the absorbed dose in Solid Water directly. The sensitive air-volume of the extrapolation chamber is controlled through the movement of the chamber piston by means of a micrometer mounted to the phantom body. The relative displacement of the piston is monitored by a calibrated mechanical distance travel indicator with a precision on the order of 0.002 mm. Irradiations were carried out with cobalt-60 gamma rays, x-ray beams ranging from 4 to 18 MV, and electron beams between 6 and 22 MeV. The absorbed dose at a given depth in Solid Water is proportional to the ionization gradient measured in the Bragg-Gray cavity region with an extrapolation chamber embedded in the Solid Water phantom. The discrepancies between the doses determined in Solid Water with our uncalibrated extrapolation chamber and doses obtained with a calibrated standard thimble ionization chamber are at most 1% for photon and electron beams at all megavoltage clinical energies. Uncalibrated extrapolation chamber thus offer a simple and practical alternative to other techniques used in output measurements of megavoltage photon and electron machines. PMID:9127299

Zankowski, C E; Podgorsak, E B

1997-04-01

409

Gas and aerosol wall losses in Teflon film smog chambers  

SciTech Connect

Large smog chambers (approx.60 m/sup 3/) constructed of FEP Teflon film are frequently used to study photochemistry and aerosol formation in model chemical systems. In a previous paper a theory for aerosol wall loss rates in Teflon film smog chambers was developed; predicted particle loss rates were in good agreement with measured rates. In the present paper, measurements of wall deposition rates and the effects of wall losses on measurements of gas-to-particle conversion in smog chambers are discussed. Calculations indicate that a large fraction of the aerosol formed in several smog chamber experiments was on the chamber walls at the end of the experiment. Estimated values for particulate organic carbon yield for several precursor hydrocarbons increased by factors of 1.3-6.0 when wall deposition was taken into account. The theory is also extended to loss rates of gaseous species. Such loss rates are either limited by diffusion through a concentration boundary layer near the surface or by uptake at the surface. It is shown that for a typical 60-m/sup 3/ Teflon film smog chamber, gas loss rates are limited by surface reaction rates if mass accommodation coefficients are less than 6 x 10/sup -6/. It follows that previously reported loss rates of several gases in a chamber of this type were limited by surface reactions.

McMurry, P.H.; Grosjean, D.

1985-12-01

410

Texas Facilities Commission's Facility Management Strategic Plan  

E-print Network

Texas Facilities Commission?s Facility Management Strategic Plan Jorge A. Ramirez Deputy Executive Director Building Operations & Plant Management ESL-IC-09-11-12 Proceedings of the Ninth International Conference for Enhanced Building Operations..., Texas, November 17 - 19, 2009 Facility Strategic Plan ?High Performance Building Approach ? Envelope ? Load Reduction ? (Re)Design ? Advanced Tactics ?Building Automation ? Sub-metering ? Controls ?Commissioning ? Assessment ? Continuous ?Facility...

Ramirez, J. A.

411

A ring-shaped recombination chamber for hadron therapy dosimetry.  

PubMed

An innovative recombination chamber has been designed for estimation of stray radiation doses and quality factors in hadron therapy. The chamber allows for determination of absorbed dose and recombination index of radiation quality in phantoms at small distances from simulated organs. The chamber body and electrodes are ring shaped, so the beam may be directed through the empty centre of the ring. The ionisation of the filling gas is caused by secondary or scattered radiation and can be related to the dose absorbed in the tissues close to the irradiated target volume. PMID:24430949

Jakubowska, E; Zielczy?ski, M; Golnik, N; Gryzi?ski, M A; Krzemi?ski, L

2014-10-01

412

Cryogenic Chamber for Servo-Hydraulic Materials Testing  

NASA Technical Reports Server (NTRS)

A compact cryogenic test chamber can be cooled to approximately 5 to 6 Kelvin for materials testing. The system includes a temperature controller and multiple sensors to measure specimen temperature at different locations. The testing chamber provides a fast and easy method to perform materials testing at lower than liquid nitrogen temperature (77 K). The purpose of the chamber is to cool a composite lap shear specimen to approximately 20 K so that tensile test force and displacement data may be acquired at this cryogenic temperature range.

Francis, John J.; Tuttle, James

2009-01-01

413

Shielding effects of vacuum chambers and longitudinal space charge impedances  

E-print Network

This paper presents the shielding effects of vacuum chambers with various cross-sections on the longitudinal space charge impedances. The space charge potentials and fields of a line charge within a given reference radius simulating a uniform round beam are calculated, the associated virtual longitudinal space charge impedances are compared to each other. The approximate analytical longitudinal space charge impedances of a round beam inside rectangular chamber and between parallel plates are derived respectively, which are consistent with the simulation results in a large range of ratios of beam diameter to chamber height and in the whole wavelength spectrum.

Li, Yingjie

2014-01-01

414

Environmental Dependence of the Performance of Resistive Plate Chambers  

E-print Network

This paper reports on the performance of Resistive Plate Chambers (RPCs) as function of the gas flow rate through the chambers and of environmental conditions, such as atmospheric pressure, ambient temperature and air humidity. The chambers are read out by pads with an area of 1 x 1 cm2 and a 1-bit resolution per pad. The performance measures include the noise rate as well as the detection efficiency and pad multiplicity for cosmic rays. The measurements extended over a period of almost one year and are sensitive to possible long-term aging effects.

Bilki, Burak; May, Ed; Mavromanolakis, Georgios; Norbeck, Edwin; Repond, Jose; Underwood, David; Xia, Lei; Zhang, Qingmin

2009-01-01

415

Environmental dependence of the performance of resistive plate chambers  

NASA Astrophysics Data System (ADS)

This paper reports on the performance of Resistive Plate Chambers (RPCs) as function of the gas flow rate through the chambers and of environmental conditions, such as atmospheric pressure, ambient temperature and air humidity. The chambers are read out by pads with an area of 1 × 1 cm2 and 1-bit resolution per pad (binary readout). The performance measures include the noise rate as well as the detection efficiency and pad multiplicity for cosmic rays. The measurements extended over a period of almost one year and are sensitive to possible long-term aging effects.

Zhang, Q.; Bilki, B.; Butler, J.; May, E.; Mavromanolakis, G.; Norbeck, E.; Repond, J.; Underwood, D.; Xia, L.

2010-02-01

416

Lifetime characteristics of Micro-Strip Gas Chambers  

NASA Astrophysics Data System (ADS)

Accelerated ageing tests were performed on four test chambers using high intensity 8 keV X-rays. The effects of varying the following chamber parameters were investigated: strip metal (aluminium, gold), substrate type (Schott S8900, Desag D263) and gas mixture ( {Ar}/{DME}, {Ne}/{DME}). After initial poor ageing results from an MSGC fabricated with aluminium strips on an S8900 substrate, chambers consistently withstood total deposited charge values in excess of 100 mC/cm, with no significant loss of gain.

Duerdoth, I. P.; Freestone, J.; Lumb, N.; Snow, S.; Thompson, R. J.

1997-02-01

417

Technical Review of the Laboratory Biosphere Closed Ecological System Facility  

NASA Astrophysics Data System (ADS)

The "Laboratory Biosphere", a new closed ecological system facility in Santa Fe, New Mexico (USA) has been constructed and became operational in May 2002. Built and operated by the Global Ecotechnics consortium (Biosphere Technologies and Biosphere Foundation with Biospheric Design Inc., and the Institute of Ecotechnics), the research apparatus for intensive crop growth, biogeochemical cycle dynamics and recycling of inedible crop biomass comprises a sealed cylindrical steel chamber and attached variable volume chamber (lung) to prevent pressures caused by the expansion and contraction of the contained air. The cylindrical growing chamber is 3.7m (12 feet) long and 3.7m (12 foot) diameter, giving an internal volume of 34 m3 (1200 ft 3 ). The two crop growth beds cover 5.5 m2, with a soil depth of 0.3m (12 inches), with 12 x 1000 watt high-pressure sodium lights capable of variable lighting of 40-70 mol per m2 per day. A small soil bed reactor in the chamber can be activated to help with metabolism of chamber trace gases. The volume of the attached variable volume chamber (lung) can range between 0-11 m3 (0-400 ft 3 ). Evapotranspired and soil leachate water are collected, combined and recycled to water the planting beds. Sampling ports enable testing of water quality of leachate, condensate and irrigation water. Visual inspection windows provide views of the entire interior and growing beds. The chamber is also outfitted with an airlock to minimize air exchange when people enter and work in the chamber. Continuous sensors include atmospheric CO2 and oxygen, temperature, humidity, soil moisture, light level and water levels in reservoirs. Both "sniffer" (air ports) and "sipper" (water ports) will enable collection of water or air samples for detailed analysis. This paper reports on the development of this new soil-based bioregenerative life support closed system apparatus and its technical challenges and capabilities.

Dempster, W.; van Thillo, M.; Alling, A.; Allen, J.; Silverstone, S.; Nelson, M.

418

TSUNAMI analysis of National Ignition Facility 2-D gas dynamics phenomenon  

SciTech Connect

The tests in the chamber of National Ignition Facility will involve complex multi-dimensional dynamics phenomena. Many safety concerns relate to the ablation of the chamber material and the re-condensation of it. The x-ray induced ablation can vaporize surfaces of internal structures. The deposition of the ablated mass to the laser optics can cause significant damage to the laser optics. This study presents a typical analysis of the ablation from the target positioner in the NIF chamber with the TSUNAMI two-dimensional gas dynamics code. Results reveal that the geometry of target positioner has strong influence to the vapor mass amount and distribution over the chamber wall. The analysis done here shows that it is possible to perform parametric study for different NIF chamber design configurations.

Chen, X.M.; Peterson, P.F. [Univ. of California, Berkeley, CA (United States); Tobin, M.T. [Lawrence Livermore National Lab., CA (United States)

1994-11-01

419

TSUNAMI analysis of National Ignition Facility 2-D gas dynamics phenomenon  

Microsoft Academic Search

The tests in the chamber of National Ignition Facility will involve complex multi-dimensional dynamics phenomena. Many safety concerns relate to the ablation of the chamber material and the re-condensation of it. The x-ray induced ablation can vaporize surfaces of internal structures. The deposition of the ablated mass to the laser optics can cause significant damage to the laser optics. This

X. M. Chen; P. F. Peterson; M. T. Tobin

1994-01-01

420

Neutron Flux Characterization of the Cold Beam PGAA-NIPS Facility at the Budapest Research Reactor  

NASA Astrophysics Data System (ADS)

Reliable flux characterization is essential for facilities using neutron beams. Hence, the NIPS station at the Budapest Research Reactor has recently been equipped with neutron-tomographic equipment. The beam can also be characterized by means of a large surface wire chamber and application of the time-of-flight method. The energy distribution was measured at three horizontal positions with the surface wire chamber in pinhole geometry, while the spatial inhomogeneity was determined by means of our new neutron-tomographic equipment.

Belgya, T.; Kis, Z.; Szentmiklósi, L.

2014-05-01

421

Test of a MWPC for the LHCb Muon System at the Gamma Irradiation Facility at CERN  

E-print Network

We present the results of a test on a MWPC, of the region M3R3 of the LHCb Muon System, at the Gamma Irradiation Facility (GIF) at CERN. This was the first test of a chamber equipped with the final front end electronics. The performance of the chamber was studied with an about 100 GeV muon beam varying, by means of filters, the intensity of the photon flux reaching the detector.

Anelli, M; Felici, G; Forti, C; Lanfranchi, G; Rosellini, R; Santoni, M; Saputi, A; Sarti, A; Sciascia, B; Bocci, V; Chiodi, G; Dané, E; Iacoangeli, F; Martellotti, G; Nobrega, R; Pinci, D; Rinaldi, W; Gatta, M

2005-01-01

422

Molecular Contamination Investigation Facility (MCIF) Capabilities  

NASA Technical Reports Server (NTRS)

This facility was used to guide the development of ASTM E 1559 center dot Multiple Quartz Crystal Microbalances (QCMs), large sample and spectral effects capability center dot Several instrumented, high vacuum chamber systems are used to evaluate the molecular outgassing characteristics of materials, flight components and other sensitive surfaces. Test materials for spacecraft/instrument selection center.Test flight components for acceptable molecular outgas levels center dot Determine time/temperature vacuum bake-out requirements center. Data used to set limits for use of materials and specific components center. Provide Input Data to Contamination Transport Models -Applied to numerous flight projects over the past 20 years.

Soules, David M.

2013-01-01

423

IRIDIUM LINER FOR NASA 5 LBF CLASS MATERIAL TEST CHAMBER IRIDIUM LINER FOR ATLANTIC RESEARCH CORPORA  

NASA Technical Reports Server (NTRS)

IRIDIUM LINER FOR NASA 5 LBF CLASS MATERIAL TEST CHAMBER IRIDIUM LINER FOR ATLANTIC RESEARCH CORPORATION 5 LBF CLASS ROCKET CHAMBER 25 LBF CLASS 75 HFC 25 TAC CERAMIC COMPOSITE ROCKET CHAMBER FROM REFRACTURY COMPOSITES INC. PURCHASE ORDER C-551941-

1995-01-01

424

Photodegradation of polyaromatic hydrocarbons in passive air samplers: Field testing different deployment chambers  

USGS Publications Warehouse

Semi-permeable membrane devices (SPMDs) were loaded with deuterated anthracene and pyrene as performance reference compounds (PRCs) and deployed at a test site in four different chambers (open and closed box chamber, bowl chamber and cage chamber) for 29 days. The losses of PRCs and the uptake of polyaromatic hydrocarbons (PAHs) from the ambient air were quantified. UV-B levels measured in each deployment chamber indicated that SPMDs would be exposed to the most UV-B in the cage chamber and open box chamber. Significantly less PAHs were quantified in SPMDs deployed in the cage chamber and open box chamber compared to samplers from the other two chambers, suggesting that photodegradation of PAHs had occurred. The loss of PRCs confirmed these results but also showed that photodegradation was occurring in the closed box chamber. The bowl chamber appears to provide the best protection from the influence of direct photodegradation. ?? 2006 Elsevier Ltd. All rights reserved.

Bartkow, M.E.; Kennedy, K.E.; Huckins, J.N.; Holling, N.; Komarova, T.; Muller, J.F.

2006-01-01

425

HYLIFE-II reactor chamber mechanical design: Update  

SciTech Connect

Mechanical design features of the reactor chamber for the HYLIFE-II inertial confinement fusion power plant are presented. A combination of oscillating and steady, molten salt streams (Li{sub 2}BeF{sub 4}) are used for shielding and blast protection of the chamber walls. The system is designed for a 6 Hz repetition rate. Beam path clearing, between shots, is accomplished with the oscillating flow. The mechanism for generating the oscillating streams is described. A design configuration of the vessel wall allows adequate cooling and provides extra shielding to reduce thermal stresses to tolerable levels. The bottom portion of the reactor chamber is designed to minimize splash back of the high velocity (17 m/s) salt streams and also recover up to half of the dynamic head. Cost estimates for a 1 GW{sub e} and 2 GW{sub e} reactor chamber are presented.

House, P.A.

1992-10-28

426

19. SECOND FLOOR, CITY COMMISSION CHAMBERS, DETAIL OF ARCH WITH ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

19. SECOND FLOOR, CITY COMMISSION CHAMBERS, DETAIL OF ARCH WITH MURAL ON RIGHT OF BENCH, SHOWING PIONEERS AND ATLANTIC CITY SEAL - City Hall, Atlantic & Tennessee Avenues, Atlantic City, Atlantic County, NJ

427

Fabrication of Composite Combustion Chamber/Nozzle for Fastrac Engine  

NASA Technical Reports Server (NTRS)

The Fastrac Engine developed by the Marshall Space Flight Center for the X-34 vehicle began as a low cost engine development program for a small booster system. One of the key components to reducing the engine cost was the development of an inexpensive combustion chamber/nozzle. Fabrication of a regeneratively cooled thrust chamber and nozzle was considered too expensive and time consuming. In looking for an alternate design concept, the Space Shuttle's Reusable Solid Rocket Motor Project provided an extensive background with ablative composite materials in a combustion environment. An integral combustion chamber/nozzle was designed and fabricated with a silica/phenolic ablative liner and a carbon/epoxy structural overwrap. This paper describes the fabrication process and developmental hurdles overcome for the Fastrac engine one-piece composite combustion chamber/nozzle.

Lawerence, T.; Beshears, R.; Burlingame, S.; Peters, W.; Prince, M.; Suits, M.; Tillery, S.; Burns, L.; Kovach, M.; Roberts, K.; Clinton, R. G., Jr. (Technical Monitor)

2000-01-01

428

Fabrication of Composite Combustion Chamber/Nozzle for Fastrac Engine  

NASA Technical Reports Server (NTRS)

The Fastrac Engine developed by the Marshall Space Flight Center for the X-34 vehicle began as a low cost engine development program for a small booster system. One of the key components to reducing the engine cost was the development of an inexpensive combustion chamber/nozzle. Fabrication of a regeneratively cooled thrust chamber and nozzle was considered too expensive and time consuming. In looking for an alternate design concept, the Space Shuttle's Reusable Solid Rocket Motor Project provided an extensive background with ablative composite materials in a combustion environment. An integral combustion chamber/nozzle was designed and fabricated with a silica/phenolic ablative liner and a carbon/epoxy structural overwrap. This paper describes the fabrication process and developmental hurdles overcome for the Fastrac engine one-piece composite combustion chamber/nozzle.

Lawrence, T.; Beshears, R.; Burlingame, S.; Peters, W.; Prince, M.; Suits, M.; Tillery, S.; Burns, L.; Kovach, M.; Roberts, K.

2001-01-01

429

46. AUXILIARY CHAMBER (EAST END), LOOKING NORTHWEST AT STEAM AND ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

46. AUXILIARY CHAMBER (EAST END), LOOKING NORTHWEST AT STEAM AND FEEDWATER PIPING AND PRESSURIZER AND FLASH/BLOWOFF TANK ROOMS (LOCATION EEE) - Shippingport Atomic Power Station, On Ohio River, 25 miles Northwest of Pittsburgh, Shippingport, Beaver County, PA

430

Stereo: cylindrical drift chamber for muon decay experiments at LAMPF  

SciTech Connect

A stereo, cylindrical drift chamber has been built for use in a search for rare decay modes of the muon at LAMPF. This chamber (part of the Crystal Box detector) has 728 cells on 8 concentric annuli at alternating angles of 10/sup 0/ to 16/sup 0/ from the chamber axis and with radii from 105 to 220 mm. The basic cell cross section is (9 x 10) mm/sup 2/ and the inter-layer spacing is 4.7 mm. Preliminary results show the single-wire efficiencies to be greater than 99%. Based on results obtained from prototype chambers, we hope to achieve 170-..mu..m resolution (including multiple scattering) when TDC offsets and sense-wire locations found in a careful inspection of the endplates are added to the track-finding algorithm.

Bolton, R.D.; Carlini, R.D.; Cooper, M.D.; Frank, J.S.; Hart, V.E.; Matis, H.S.; Mischke, R.E.; Sandberg, V.D.; Sennhauser, U.

1983-01-01

431

A self-triggered readout for a time projection chamber  

E-print Network

A self-triggering readout for a time projection chamber (TPC) is presented, with applications to novel forms of data acquisition for high energy physics application. The construction and initial testing of the readout ...

Werner, Andrew Thompson, 1981-

2004-01-01

432

Dynamic behavior of valves with pneumatic chamber for reciprocating compressors  

SciTech Connect

This paper describes the dynamic behavior of valves with pneumatic chambers for reciprocating compressors. These are known as `damped valves` and are capable of reducing the impact on the valve seat and valve stopper. The characteristics of the dynamic behavior of the damped valves were clarified by calculating newly derived governing equations of valve dynamics. From the calculated results, it becomes apparent that the volume of the pneumatic chambers and the clearance between the pneumatic chamber and the valve have a large influence on the impact speed of the valves. Furthermore, the valves tend to close later for a higher compressor speed to oscillate at a larger amplitude for a lower density of gas such as hydrogen. These tendencies show that the selection of the specification of damped valves is very important. The stiffness of the valve spring and the lift of the valve also affect valve behavior as with valves without pneumatic chambers.

Kato, M.; Kurohashi, M.; Aoshima, M. [Kobe Steel, Ltd., Kobe (Japan)

1993-10-01

433

CONSTRUCTION OF AN OXYGEN CHAMBER FOR THE TREATMENT OF PNEUMONIA  

PubMed Central

1. The construction of an oxygen chamber is given. This chamber can be quickly filled with oxygen to any concentration up to 65 per cent and maintained at the desired concentration for an indefinite time. 2. The construction of ventilating system, cooling device, carbon dioxide remover, automatic oxygen analyzer, and filling and maintenance devices is given. 3. The chamber is designed so that pneumonia patients with anoxemia may be placed in it and breathe an atmosphere containing 40 to 60 per cent of oxygen. 4. The chamber is easy of ingress and egress, is economical in cost of operation, and comfortably accomodates patient and attendants so that adequate nursing and medical attention can be given at all times. PMID:19868609

Stadie, William C.

1922-01-01

434

63. REACTOR CHAMBER (BASF) FROM NORTH SHOWING NEUTRON SHIELD TANK ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

63. REACTOR CHAMBER (BASF) FROM NORTH SHOWING NEUTRON SHIELD TANK AND REACTOR PIPING (LOCATION RRR) - Shippingport Atomic Power Station, On Ohio River, 25 miles Northwest of Pittsburgh, Shippingport, Beaver County, PA

435

27. EXTENSION OF SURGE CHAMBER AND AIR PIPES TO PRESSURE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

27. EXTENSION OF SURGE CHAMBER AND AIR PIPES TO PRESSURE LINE, HIGHLINE PUMPING PLANT. December 11, 1920 - Highline Canal & Pumping Station, South side of Salt River between Tempe, Phoenix & Mesa, Tempe, Maricopa County, AZ

436

Dirofilaria in the Anterior Chamber: A Rare Occurrence  

PubMed Central

Dirofilariasis is a parasitic infection of the carvivores that may present as a zoonotic infestation in humans. Systemic involvement in man is subcutaneous, pulmonary, or ocular. We report a rare occurrence of ocular dirofilariasis in a 25-year-old male patient who presented with pain and redness in the eye. A live, white, coiled, and highly motile worm was present in the anterior chamber. The worm, however, could not be detected in the anterior chamber, posterior segment, or the angle of the anterior chamber when the patient was taken to the operating room for surgical removal of the worm. The patient was made to lie prone till the worm reappeared in the anterior chamber and was removed by paracentesis. The worm was identified as Dirofilaria repens on the basis of microscopic and histopathological examination. PMID:22837635

Chopra, Rupali; Bhatti, Sattar M.; Mohan, Sangeetha; Taneja, Neha

2012-01-01

437

Dirofilaria in the anterior chamber: a rare occurrence.  

PubMed

Dirofilariasis is a parasitic infection of the carvivores that may present as a zoonotic infestation in humans. Systemic involvement in man is subcutaneous, pulmonary, or ocular. We report a rare occurrence of ocular dirofilariasis in a 25-year-old male patient who presented with pain and redness in the eye. A live, white, coiled, and highly motile worm was present in the anterior chamber. The worm, however, could not be detected in the anterior chamber, posterior segment, or the angle of the anterior chamber when the patient was taken to the operating room for surgical removal of the worm. The patient was made to lie prone till the worm reappeared in the anterior chamber and was removed by paracentesis. The worm was identified as Dirofilaria repens on the basis of microscopic and histopathological examination. PMID:22837635

Chopra, Rupali; Bhatti, Sattar M; Mohan, Sangeetha; Taneja, Neha

2012-01-01

438

Novel method for cleaning a vacuum chamber from hydrocarbon contamination  

SciTech Connect

A novel method for cleaning a high vacuum chamber is presented. This method is based on concurrent in situ high-energetic UV light activation of contaminants located in the residual gas and at the vacuum chamber surfaces as well as the in situ generation of highly reactive ozone. Ozone oxidizes the contaminants to volatile species. Investigations by energy-dispersive x-ray analysis of residual gas depositions and mass-spectroscopy measurements of the residual gas in the vacuum chamber identify the contaminant species as hydrocarbons. After a cleaning period of 8 h, a decrease in measured chamber contamination by about 90% could be achieved according to atomic force microscope analysis. Mass spectroscopy measurements using a residual gas analyzer indicate the creation of volatile, carbonaceous species during the cleaning process.

Wanzenboeck, H. D.; Roediger, P.; Hochleitner, G.; Bertagnolli, E.; Buehler, W. [Vienna University of Technology, Floragasse 7/1, A-1040 Vienna (Austria); Carl Zeiss NTS GmbH, Carl-Zeiss-Str. 56, Oberkochen 73447 (Germany)

2010-11-15

439

Fabrication process for combustion chamber/nozzle assembly  

NASA Technical Reports Server (NTRS)

An integral, lightweight combustion chamber/nozzle assembly for a rocket engine has a refractory metal shell defining a chamber of generally frusto-conical contour. The shell communicates at its smaller end with a rocket body, and terminates at its larger end in a generally contact contour, which is open at its terminus and which serves as a nozzle for the rocket engine. The entire inner surface of the refractory metal shell has a thermal and oxidation barrier layer applied thereto. An ablative silica phenolic insert is bonded to the exposed surface of the thermal and oxidation barrier layer. The ablative phenolic insert provides a chosen inner contour for the combustion chamber and has a taper toward the open terminus of the nozzle. A process for fabricating the integral, lightweight combustion chamber/nozzle assembly is simple and efficient, and results in economy in respect of both resources and time.

Myers, W. Neill (Inventor); Cornelius, Charles S. (Inventor)

2001-01-01

440

Combustion Chamber/Nozzle Assembly and Fabrication Process Therefor  

NASA Technical Reports Server (NTRS)

An integral lightweight combustion chamber/nozzle assembly for a rocket engine has a refractory metal shell defining a chamber of generally frusto-conical contour. The shell communicates at its larger end with a rocket body, and terminates at its smaller end in a tube of generally cylindrical contour, which is open at its terminus and which serves as a nozzle for the rocket engine. The entire inner surface of the refractory metal shell has a thermal and oxidation barrier layer applied thereto. An ablative silica phenolic insert is bonded to the exposed surface of the thermal and oxidation barrier layer. The ablative phenolic insert provides a chosen inner contour for the combustion chamber and has a taper toward the open terminus of the nozzle. A process for fabricating the integral, lightweight combustion chamber/nozzle assembly is simple and efficient, and results in economy in respect of both resources and time.

Myers, W. Neill (Inventor); Cornelius, Charles S. (Inventor)

2000-01-01

441

A new inner drift chamber for BESIII MDC  

E-print Network

Due to the beam related background, the inner chamber of BESIII MDC has aging effect after 5 years running. The gains of the inner chamber cells decrease obviously, and the max gain decrease is about 26% for the first layer cells. A new inner drift chamber with eight stereo sense wire layers as a backup for MDC is under construction, which is almost the same as the current one but using stepped endplates to shorten the wire length beyond the effective solid angle. This new structure will be of benefit to reducing the counting rate of single cell. The manufacture of each component is going smoothly, and the new inner drift chamber will be finished by the end of April 2014.

M. Y. Dong; Z. H. Qin; X. Y. Ma; J. Zhang; J. Dong; W. Xie; Q. L. Xiu; X. D. Ju; R. G. Liu; Q. Ouyang

2014-03-07

442

Lens opacities after posterior chamber phakic intraocular lens implantation  

Microsoft Academic Search

PurposeTo describe a case series to determine the incidence of lens opacities after posterior chamber phakic intraocular lens (IOL) implantation (STAAR Surgical, Monrovia, CA) for very high ametropias.

C. ésar A Sánchez-Galeana; Ronald J Smith; Donald R Sanders; Francisco X Rodríguez; Sergio Litwak; Miguel Montes; Arturo S Chayet

2003-01-01

443

Modelling Contribution of Biogenic VOCs to New Particle Formation in the Jülich Plant Atmosphere Chamber  

NASA Astrophysics Data System (ADS)

Biogenic VOCs are substantially emitted from vegetation to atmosphere. The oxidation of BVOCs by OH, O3, and NO3 in air generating less volatile compounds may lead to the formation and growth of secondary organic aerosol, and thus presents a link to the vegetation, aerosol, and climate interaction system (Kulmala et al, 2004). Studies including field observations, laboratory experiments and modelling have improved our understanding on the connection between BVOCs and new particle formation mechanism in some extent (see e.g. Tunved et al., 2006; Mentel et al., 2009). Nevertheless, the exact formation process still remains uncertain, especially from the perspective of BVOC contributions. The purpose of this work is using the MALTE aerosol dynamics and air chemistry box model to investigate aerosol formation from reactions of direct tree emitted VOCs in the presence of ozone, UV light and artificial solar light in an atmospheric simulation chamber. This model employs up to date air chemical reactions, especially the VOC chemistry, which may potentially allow us to estimate the contribution of BVOCs to secondary aerosol formation, and further to quantify the influence of terpenes to the formation rate of new particles. Experiments were conducted in the plant chamber facility at Forschungszentrum Jülich, Germany (Jülich Plant Aerosol Atmosphere Chamber, JPAC). The detail regarding to the chamber facility has been written elsewhere (Mentel et al., 2009). During the experiments, sulphuric acid was measured by CIMS. VOC mixing ratios were measured by two GC-MS systems and PTR-MS. An Airmodus Particle size magnifier coupled with a TSI CPC and a PH-CPC were used to count the total particle number concentrations with a detection limit close to the expected size of formation of fresh nanoCN. A SMPS measured the particle size distribution. Several other parameters including ozone, CO2, NO, Temperature, RH, and flow rates were also measured. MALTE is a modular model to predict new aerosol formation in the lower troposphere, developed by Boy, et al. (2006). We first evaluate the modelled results with measurements, and further we investigate the influence of different order of magnitude of terpene mixing ratios, especially isoprene and monoterpenes to the most important parameter of new particles formation, i.e. the formation rate (J1). Also, the influence of varying organic source rates on the sulphuric acid concentration available for particle formation is discussed. M. Boy et al., (2006). Atmos. Chem. Phys., 6, 4499-4517. M. Kulmala et al., (2004). Atmos. Chem. Phys., 4, 557-562. P. Tunved et al., (2006). Science, 14, 261-263. Th. F. Mentel et al., (2009). Atmos. Chem. Phys., 9, 4387-4406.

Liao, L.; Boy, M.; Mogensen, D.; Mentel, T. F.; Kleist, E.; Kiendler-Scharr, A.; Tillman, R.; Kulmala, M. T.; Dal Maso, M.

2012-12-01

444

Outdoor smog chamber experiments: reactivity of methanol exhaust. Part 2. Quality assurance and data processing system description  

SciTech Connect

The report describes the Quality Assurance and Data Processing procedures and systems used at the UNC Outdoor Smog Chamber Facility. The primary product of research conducted at this facility is information in the form of measurements of reactants and products in photochemical systems and measurements of the critical parameters that influence the chemical transformations system. Generating useful data begins with understanding the goals of the project and the special needs and concerns of conducting a successful smog-chamber operation. The system components are designed to collect, transfer, process, and report accurate, high-resolution data without loss or distortion. The system components in the Quality Assurance and Data Processing system are: people, hardware, software, checklists, and data bases. Quality-assurance checks are made at every level of the program. Pressurized gas-tank and liquid mixtures were used to establish experimental conditions of HC assuring consistency throughout the program. Several NBS traceable standards and liquid injections into the chamber used for calibration have been intercompared and show good agreement.

Jeffries, H.E.; Sexton, K.G.; Kamens, R.M.; Holleman, M.S.

1985-09-01

445

Measurements of radiation quality factors using a recombination chamber  

SciTech Connect

The recombination chamber technique has been described in a CERN report by Sullivan and Baarli. In this method, one uses the fact that a high pressure ion chamber operated at a voltage beneath its plateau will measure a greater response to radiation of low LET than to radiation of high LET in fields of equivalent absorbed dose rate. This report describes a calibration procedure and results obtained in accelerator radiation fields. 8 references, 6 figures. (ACR)

Cossairt, J.D.; Grobe, D.W.; Gerardi, M.A.

1984-03-01

446

Chamber technology concepts for inertial fusion energy: Three recent examples  

SciTech Connect

The most serious challenges in the design of chambers for inertial fusion energy (IFE) are 1) protecting the first wall from fusion energy pulses on the order of several hundred megajoules released in the form of x rays, target debris, and high energy neutrons, and 2) operating the chamber at a pulse repetition rate of 5-10 Hz (i.e., re-establishing, the wall protection and chamber conditions needed for beam propagation to the target between pulses). In meeting these challenges, designers have capitalized on the ability to separate the fusion burn physics from the geometry and environment of the fusion chamber. Most recent conceptual designs use gases or flowing liquids inside the chamber. Thin liquid layers of molten salt or metal and low pressure, high-Z gases can protect the first wall from x rays and target debris, while thick liquid layers have the added benefit of protecting structures from fusion neutrons thereby significantly reducing the radiation damage and activation. The use of thick liquid walls is predicted to 1) reduce the cost of electricity by avoiding the cost and down time of changing damaged structures, and 2) reduce the cost of development by avoiding the cost of developing a new, low-activation material. Various schemes have been proposed to assure chamber clearing and renewal of the protective features at the required pulse rate. Representative chamber concepts are described, and key technical feasibility issues are identified for each class of chamber. Experimental activities (past, current, and proposed) to address these issues and technology research and development needs are discussed.

Meier, W.R.; Moir, R.W. [Lawrence Livermore National Lab., CA (United States); Abdou, M.A. [California Univ., Los Angeles, CA (United States)

1997-02-27

447

Depressive behavior in young monkeys subjected to vertical chamber confinement  

Microsoft Academic Search

Confined 4 young male rhesus monkeys in vertical chambers for 6 wk. Ss' subsequent behavior over a 9-mo period in both a home-cage and playroom situation was compared with that of 4 controls housed individually or in pairs. In comparison to both control groups, chambered Ss exhibited excessive amounts of self-clasp and huddle behavior, abnormally low levels of locomotion and

Stephen J. Suomi; Harry F. Harlow

1972-01-01

448

Power Plant and Fusion Chamber Considerations for Fast Ignition  

Microsoft Academic Search

A large number of inertial fusion energy (IFE) chamber concepts have been proposed and analyzed to various levels of detail [1, 2]. A smaller number of detailed power plant design studies (i.e., studies considering self-consistent integration of targets, drivers and chambers) have also been completed for both direct-drive and indirect-drive, central ignition (CI) targets [3-5]. There have not been any

W R Meier; W J Hogan

2005-01-01

449

Cleaning of a thermal vacuum chamber with shrouds in place  

NASA Technical Reports Server (NTRS)

In February, 1991, a failure of a rotary booster pump caused the diffusion pumps to backstream into a 10 ft x 15 ft thermal vacuum chamber. Concerns existed about the difficulty of removing and reinstalling the shrouds without causing leaks. The time required for the shroud removal was also of concern. These concerns prompted us to attempt to clean the chamber without removing the shrouds.

Bond, William R.

1992-01-01

450

Radiation damage to tetramethylsilane and tetramethylgermanium ionization chambers  

SciTech Connect

Two detector media suitable for a warm liquid, ionization chamber filled with tetramethylsilane (TMS) and tetramethylgermanium (TMG) were exposed to [gamma] radiation form a [sup 60]Co source up to dose 579 Gray and 902 Gray, respectively. The electron lifetimes and the free ion yields were measured as a function of accumulated radiation dose. A similar behavior of the electron lifetimes and the free ion yields with increasing radiation does was observed between the TMS and TMG ionization chambers.

Hoshi, Y.; Higuchi, M.; Oyama, K. (Tohoku Gakuin Univ., Tagajo (Japan). Dept. of Applied Physics) (and others)

1994-08-01

451

Transverse wakefields due to asymmetric protrusions into a vacuum chamber  

NASA Astrophysics Data System (ADS)

We analyze the effect of a wakefield caused by an asymmetric protrusion inside the accelerator vacuum chamber. The asymmetry leads to a transverse kick on the beam and an increase of the projected transverse beam emittance. Calculations are done for a model rectangular protrusion in a vacuum chamber of rectangular cross-section. Based on our analysis, numerical estimates are given for the SuperKEKB accelerator in KEK, Japan, and TLEP-W proposal at CERN.

Stupakov, Gennady; Zhou, Demin

2014-11-01

452

Laser calibration system for the CERES Time Projection Chamber  

E-print Network

A Nd:YAG laser was used to simulate charged particle tracks at known positions in the CERES Time Projection Chamber at the CERN SPS. The system was primarily developed to study the response of the readout electronics and to calibrate the electron drift velocity. Further applications were the determination of the gating grid transparency, the chamber position calibration, and long-term monitoring of drift properties of the gas in the detector.

Dariusz Miskowiec; Peter Braun-Munzinger

2008-01-31

453

Design of the target area for the National Ignition Facility  

SciTech Connect

The preliminary design of the target area for the National Ignition Facility has been completed. The target area is required to meet a challenging set of engineering system design requirements and user needs. The target area must provide the appropriate conditions before, during, and after each shot. The repeated introduction of large amounts of laser energy into the chamber and subsequent target emissions represent new design challenges for ICF facility design. Prior to each shot, the target area must provide the required target illumination, target chamber vacuum, diagnostics, and optically stable structures. During the shot, the impact of the target emissions on the target chamber, diagnostics, and optical elements is minimized and the workers and public are protected from excessive prompt radiation doses. After the shot, residual radioactivation is managed to allow the required accessibility. Diagnostic data is retrieved, operations and maintenance activities are conducted, and the facility is ready for the next shot. The target area subsystems include the target chamber, target positioner, structural systems, target diagnostics, environmental systems, and the final optics assembly. The engineering design of the major elements of the target area requires a unique combination of precision engineering, structural analysis, opto-mechanical design, random vibration suppression, thermal stability, materials engineering, robotics, and optical cleanliness. The facility has been designed to conduct both x- ray driven targets and to be converted at a later date for direct drive experiments. The NIF has been configured to provide a wide range of experimental environments for the anticipated user groups of the facility. The design status of the major elements of the target area is described.

Foley, R.J.; Karpenko, V.P.; Adams, C.H. [and others

1997-01-01

454

Complete fabrication of target experimental chamber and implement initial target diagnostics to be used for the first target experiments in NDCX-1  

SciTech Connect

The Heavy Ion Fusion Science Virtual National Laboratory (HIFS-VNL) has completed the fabrication of a new experimental target chamber facility for future Warm Dense Matter (WDM) experiments, and implemented initial target diagnostics to be used for the first target experiments in NDCX-1. The target chamber has been installed on the NDCX-I beamline. This achievement provides to the HIFS-VNL unique and state-of-the-art experimental capabilities in preparation for the planned target heating experiments using intense heavy ion beams.

Bieniosek, F.M.; Bieniosek, F.M.; Dickinson, M.R.; Henestroza, E.; Katayanagi, T.; Jung, J.Y.; Lee, C.W.; Leitner, M.; Ni, P.; Roy, P.; Seidl, P.; Waldron, W.; Welch, D.

2008-06-09

455

Space shuttle orbit maneuvering engine reusable thrust chamber program  

NASA Technical Reports Server (NTRS)

Reusable thrust chamber and injector concepts were evaluated for the space shuttle orbit maneuvering engine (OME). Parametric engine calculations were carried out by computer program for N2O4/amine, LOX/amine and LOX/hydrocarbon propellant combinations for engines incorporating regenerative cooled and insulated columbium thrust chambers. The calculation methods are described including the fuel vortex film cooling method of combustion gas temperature control, and performance prediction. A method of acceptance of a regeneratively cooled heat rejection reduction using a silicone oil additive was also demonstrated by heated tube heat transfer testing. Regeneratively cooled thrust chamber operation was also demonstrated where the injector was characterized for the OME application with a channel wall regenerative thrust chamber. Bomb stability testing of the demonstration chambers/injectors demonstrated recovery for the nominal design of acoustic cavities. Cavity geometry changes were also evaluated to assess their damping margin. Performance and combustion stability was demonstrated of the originally developed 10 inch diameter combustion pattern operating in an 8 inch diameter thrust chamber.

Senneff, J. M.

1975-01-01

456

Maintaining Stimulant Waveforms in Large Volume Microfluidic Cell Chambers  

PubMed Central

Stimulation of cells with temporal waveforms can be used to observe the frequency-dependent nature of cellular responses. The ability to produce and maintain the temporal waveforms in spite of the broadening processes that occur as the wave travels through the microfluidic system is critical for observing dynamic behaviors. Broadening of waves in microfluidic channels has been examined, but the effect that large-volume cell chambers have on the waves has not. In this report, a sinusoidal glucose wave delivered to a 1 mm diameter cell chamber using various microfluidic channel structures was simulated by finite element analysis with the goal of minimizing the broadening of the waveform in the chamber and maximizing the homogeneity of the concentration in the chamber at any given time. Simulation results indicated that increasing the flow rate was the most effective means to achieve these goals, but at a given volumetric flow rate, geometries that deliver the waveform to multiple regions in the chamber while maintaining a high linear velocity produced sufficient results. A 4-inlet geometry with a 220 ?m channel width gave the best result in the simulation and was used to deliver glucose waveforms to a population of pancreatic islets of Langerhans. The result was a stronger and more robust synchronization of the islet population as compared to when a non-optimized chamber was used. This general strategy will be useful in other microfluidic systems examining the frequency-dependence nature of cellular behavior. PMID:24244207

Zhang, Xinyu; Dhumpa, Raghuram; Roper, Michael G.

2013-01-01

457

An Improved Chamber for Direct Visualisation of Chemotaxis  

PubMed Central

There has been a growing appreciation over the last decade that chemotaxis plays an important role in cancer migration, invasion and metastasis. Research into the field of cancer cell chemotaxis is still in its infancy and traditional investigative tools have been developed with other cell types and purposes in mind. Direct visualisation chambers are considered the gold standard for investigating the behaviour of cells migrating in a chemotactic gradient. We therefore drew up a list of key attributes that a chemotaxis chamber should have for investigating cancer cell chemotaxis. These include (1) compatibility with thin cover slips for optimal optical properties and to allow use of high numerical aperture (NA) oil immersion objectives; (2) gradients that are relatively stable for at least 24 hours due to the slow migration of cancer cells; (3) gradients of different steepnesses in a single experiment, with defined, consistent directions to avoid the need for complicated analysis; and (4) simple handling and disposability for use with medical samples. Here we describe and characterise the Insall chamber, a novel direct visualisation chamber. We use it to show GFP-lifeact transfected MV3 melanoma cells chemotaxing using a 60x high NA oil immersion objective, which cannot usually be done with other chemotaxis chambers. Linear gradients gave very efficient chemotaxis, contradicting earlier results suggesting that only polynomial gradients were effective. In conclusion, the chamber satisfies our design criteria, most importantly allowing high NA oil immersion microscopy to track chemotaxing cancer cells in detail over 24 hours. PMID:21179457

Muinonen-Martin, Andrew J.; Veltman, Douwe M.; Kalna, Gabriela; Insall, Robert H.

2010-01-01

458

Study of the PTW microLion chamber temperature dependence.  

PubMed

The use of liquid ionization chambers in radiotherapy has grown during the past few years. While for air ionization chambers the k(TP) correction for air mass density due to pressure and temperature variations is well known, less work has been done on the case of liquid ionization chambers, where there is still the need to take into account the influence of temperature in the free ion yield. We have measured the PTW microLion isooctane-filled ionization chamber temperature dependence in a ~ ±10 °C interval around the standard 20 °C room temperature for three operation voltages, including the manufacturer recommended voltage, and two beam qualities, (60)Co and 50 kV x-rays. Within the measured temperature range, the microLion signal exhibits a positive linear dependence, which is around 0.24% K(-1) at 800 V with (60)Co irradiation. This effect is of the same order of magnitude as the T dependence found in air ionization chambers, but its nature is completely different and its sign opposite to that of an air chamber. Onsager theory has been used to model the results and is consistent with this linear behaviour. However, some inconsistencies in the modelling of the 50 kV x-ray results have been found that are attributed to the failure of Onsager's isolated pair assumption for such radiation quality. PMID:24787030

Gómez, F; González-Castaño, D; Díaz-Botana, P; Pardo-Montero, J

2014-06-01

459

Study of the PTW microLion chamber temperature dependence  

NASA Astrophysics Data System (ADS)

The use of liquid ionization chambers in radiotherapy has grown during the past few years. While for air ionization chambers the kTP correction for air mass density due to pressure and temperature variations is well known, less work has been done on the case of liquid ionization chambers, where there is still the need to take into account the influence of temperature in the free ion yield. We have measured the PTW microLion isooctane-filled ionization chamber temperature dependence in a ˜ ±10 °C interval around the standard 20 °C room temperature for three operation voltages, including the manufacturer recommended voltage, and two beam qualities, 60Co and 50 kV x-rays. Within the measured temperature range, the microLion signal exhibits a positive linear dependence, which is around 0.24% K-1 at 800 V with 60Co irradiation. This effect is of the same order of magnitude as the T dependence found in air ionization chambers, but its nature is completely different and its sign opposite to that of an air chamber. Onsager theory has been used to model the results and is consistent with this linear behaviour. However, some inconsistencies in the modelling of the 50 kV x-ray results have been found that are attributed to the failure of Onsager's isolated pair assumption for such radiation quality.

Gómez, F.; González-Castaño, D.; Díaz-Botana, P.; Pardo-Montero, J.

2014-06-01

460

meters in CO2 euthanasia chambers. All CO2 euthanasia chambers in both  

E-print Network

facilities and laboratory areas are meeting the standards of the Animal Welfare Act Regulations and the Guide for the "Guidance on Departures from the Provisions of the Guide for the Care and Use of Laboratory Animals". OLAW" statement changes, there will be discussions at the Animal Program Advisory Committee (APAC). In February

Bushman, Frederic